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VOLUME-III TECHNICAL SPECIFICATI - DOC - DOC

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					      TS 1




  VOLUME-III
  TECHNICAL
SPECIFICATION
                                    TS 1

                        ANNEXURE - IV
DETAIL ED SP EC IFICATI ON AN D TECHNI CAL P A RTICUL ARS
             FOR DIS TRIB UT ION TR ANSFO R MERS

Scope :-   The specif ication covers the design, manuf acture testi ng
           and inspec tion b ef ore dispatch an d d eliver y at pla ces
           an yw here in M.P. of the transf ormers listed in Schedule -I.

           The   specif ication   covers   oil   i mmersed.    Natural l y oil
           cooled (t ype ONA N), outdoor t ype. Three phase, 50 Hz,
           11/433    KV    step   down     distr ibuti on   transf or mers   of
           capacities 2 5 , 63 , 100 , 200 , 315 & 500 KVA.

2.         Applicable Stand ers :-      (a) Unles s otherwise modif ied :
           The specif ication, the tran sf ormers shall co mpl y w ith the
           require ment s of ISS : 1180 (latest issue) 2026 (lat est
           issue) and REC specif ication 2/19 78 and ISS : 20 99
           (Latest issue) t he bushings use d sh all conf orm to I S S :
           2099 & 33 47 (late s t issue) exce pt as mo dif ied herein.
(B)        Ty pe:-
i)         The transf ormer s shall be double w ound, three phase oil
           immersed, oil nat ural air natural c ooled (t yp e " ONA N"),
           core t ype suit able f or out door install ation tropica l cli mate
           and shall be insul ated with DPC in s ulation on HV & LV
           windings. Insulation should be of temp erature cl ass as per
           the te mperat ure ris e stipulated in this specif ication.
ii)        The neutra l poi n t of the secon da r y (LV windin g) i s
           intended f or solidl y eart hed s yst e m a nd should be brou ght
           out to a separate insulated ter min al, enabling exter nal
           insertion of a current transf ormer in the earth lead to be
           connected whereve r required.
                                       TS 2

                            Climatic Conditions


i)     Peak outdo or te mp erature                : 50 0 C. mini mu m
                                                    (50 0 C + 50 0 C)
ii)    Maxi mu m oil te mp erature                  (50 0 C + 45 0 C)
                                                    95 0   C    unde r   ma x.
                                                    Te mperature . max
                                                    load condit ions
iii)   Maxi mu m relative hu midit y                95%        (so me     t ime
                                                    approx.         satura tion
                                                    point)
iv)    Mini mu m relative hu midit y                10%
v)     Average No . of thunderstorm                 40 da ys
       da ys per an nu m.
vi)    Average nu mber of rain y da ys              90 da ys
vii)   Nu mber of months of tropical                3 months
       ma n soon c onditio ns.
viii) Average ann ual rainf all                     125 c m.
ix)    Wi nd press ure                              100 kg/ m 2
x)     Altitudes not exce ed ing                    1000 meter s.


3.0         RATING S:
            Pri mar y vo ltage                -    11 KV
            Secondar y voltage                -    0.433 KV
                    The windings of th e transf ormers sh al l be connected
            in delta on pri mar y s ide and star on the secon dar y sid e.
            The neutral of the LT winding shall be brought out to a
            separate Ter minal. The vector g roup s hall be D yn -11.
4.0         Te mperat ure rise: -
            Te mperature ris e f or top oil over an ambient of 50 0 C
            should be 4 5 0 C ma x. ( Meas ured b y th er mo me ter as per
                                 TS 3


         IS-2026) Te mperat ure rise f or winding over an a mbient of
         50 0 C should b e 50 0 C ma x ( measu red b y resista nce in
         accordance with IS: 2026)

5.0      No Load voltage r ating:-

         The No Load Vol t age ratio shall be 11000/433 -250 Vo lts
         f or all capacities.

6.0      Taps:-

         No taping s shall be provide d f or tr ansf ormers up to 100
         KVA ratin g. Fo r ratings 200 KVA to 500 KV A tapi ngs
         shall be provi ded o n the high voltage winding f or variati on
         of HV voltage within a range of + 3 to ( -) 9% in the steps
         of 3%.
         Tap changing sh all be carried o ut b y means of an
         externall y operat e d self position switch and when the
         transf ormer is ree nergized co ndition , switch positio n No.1
         shall corres pond t o the maxi mu m p l us tapping . Each t ap
         change sh all res ult in varia tion of 3% in volt age. Pr ovisi on
         shall be made f or locking the tap ing switch han dle in
         position S uitable alu minu m a nodize d plate shall b e f ixed
         f or tap changing s witch to kn ow the position N o. of tap .


7.0      Design and Construction :-
Core :
a.       Material :- CRGO Sheet
b.       The core shall be of high grade cold rolled grain ori ent
         annealed st eel la minations h aving l o w loss a nd goo d gr ade
         properties, c oated with hot oi l pro of insulation, bol ted
         together and to th e f rames f irml y to prevent vibration or
                                     TS 4
           noise: All cla mp in g bolts shall be ef f ectivel y insul ated b y
           chro mate a nd pap er. The co mplete design of core mu st
           have per manen c y of the core losses with conti n uous
           working of transfor mers. The value of the f lux densit y
           allowed in th e des ign and grade of l ami nation used sh all
           be clearl y sta ted in the of f er.
c.         The transf or mer c ore shall not be s aturated f or an y v alue
           of V/f ra tio to t he extent of 112.5% of the rate d val ue of
           V/f ratio (i.e. 11KV/50 due to co mbi ned eff ect of voltage
           and f requenc y) u p to 12.5% on an y t apping with out
           injuries hea ting a t f ull load condit ion and w ill not get
           saturated. The sup plier shall f urnish nec essar y desig n data
           in support of this s ituation.
d.         Flux Density :- Flu x densit y at rated voltage a nd f reque nc y
           shall not exceed b e mor e than 1.55 We bbers per sq. m eter
           No. load curre nt a t rated voltage an d at 1 12.5% of ra ted
           voltage sha ll not e xceed the val ue s gi ven below.

KVA      Percentage of rate d f ull load current
         At 100 percent                              At 112.5 percent
         Rated volta ge                              Rated volta ge
         3                                                     6
100      2.5                                                   5
200      2                                                     4
315      2                                                     4
500      1.5                                                   3

Test f or magnetic balance b y conn e cting the LV phas e b y phase to
rated phase voltag e and meas ure men t of an -bn-cn. Vo ltage will b e
carried out.
(f )       Details of Core:-
S.            Particulars                          Rating in KVA
No.                                         63    100 200 315        500
 i) No. of steps (Min. )                     5     5     7    7       9
ii) Dia meter of core ( Min.) mm            100   115 155 170        195
                                      TS 5
iii)   Eff ective core are sq. c m.          70    92   160   200     272

iv)          Core Cla mping :-
a)           Channel siz e      -     75 x 40 mm               125 x 65 mm
                                                               100 x 50 mm
b)           Bolt dia. mm/Nos .-      12 mm/2N os.      ------16 mm/ 2Nos-- -
                                      (at each end)            (at each end)
             High tensile Bolts shall be used in parallel at each end.
c)           Tie bots        - 4 Nos . of 12 mm dia . - 8N os. of 16mm dia
                                                        High tensile steel
Roads to b e painte d with zinc chro ma te & ef f ectivel y in sulated.
(d)          Top & botto m yo k e should be con str ucted in single p ie ce
             of CRGD la minati on.
(e)          The top yoke ch an nels to be reinf orc ed b y MS Flat of 50x6
             KS MM a t equal distance, if hole c utting is d one f or LT
             Laser so as to avoid bending of channel.
(f )         core Base and bott om yo ke sha ll be supported with 75 mm
             x 40 mm MS Cha n nel properl y bolted together. I n no case,
             f lats cut channels s hall be accep ted.
(g)          All chan nels, top and botto m yoke Nut Bolts; Tie r ods
             shall be painted with oil and c orr osion res istant pa int
             bef ore of .
(h)          Core should be pr operl y e arthed thr ough copper strip. On
             end of copper str ip should be i nse rted deepl y int o c ore
             lamination s and other end bolted with the core clampi ng
             channel.
3.0          Winding s:
a)           Materials: - Dou ble paper cover Alu minu m C ondu ctor
             shall be used f or r atings up - to 20 0 K VA. For ratings ab ove
             200 KVA doub le p aper covered electr ol yt ic copper sha ll be
             used.
                                     TS 6
b)        Current De nsit y f or HV & LV should not be mor e than 2.8
          A/sq mm. For cop per and 1.6 A mp ere per sq . mm. For
          alu minu m conduct or.

C)        HV Cross section s hall not be less than : -
i)        63 KVA             -              1.39 SQ MM.
ii)       100 KVA            -              2.27 SQ MM.
iii)      200 KVA            -              3.79 SQ MM.
iv)       315 KVA            -              3.40 SQ MM.
v)        500 KVA            -              5.40 SQ MM.

d)        LV Cross section s hall not be less tha n : -
i)        63 KVA             -              52.5 SQ MM.
ii)       100 KVA            -              86.0 SQ MM.
iii)      200 KVA            -              168.0 SQ MM.
iv)       315 KVA            -              156.0 SQ MM.
v)        500 KVA            -              238.0 SQ MM.

Note :-   LV Wi nding shal l be in even la yer s so that the neutral
          f ormation will be a t top.

e)        HV wind ing res ist ance at ro o m te mp erature 20 0 C with 5%
          tolerance sh ould n ot be more than wi ll be at top.
i)        200 KVA            -              14.52 Oh ms.
ii)       315 KVA            -              7.07 Oh ms.
iii)      500 KVA            -              3.655 Oh ms.

f)        LV winding resist ance at roo m te mp erature 20 0 C with 5%
          tolerance sh ould n ot more tha n.
i)        200 KVA            -              0.00456 O h ms.
ii)       315 KVA            -              0.00278 Oh ms.

4.0       Losses a nd I mpedance :-
                 The losses a nd i mp edance f or various ratings of
          transf ormer s   shou ld    be    as   shown   below   s ubject   to
                                          TS 7
              tolerance as pe r. I. S. 118 0/2026 and shall be calcul ated at
              75 0 C as per li mi t specif ied. For 63 to 100 K VA no
              tolerance.
              Shall be per missib l e or no Loa d and L oad losses.
 S.        Rating in          No Load Loss         Load Lo ss of     Impedan ce
 No.         KVA                 (Watts)           75 0 C (Watts)       (%)
  i)        63 KVA                 180                   1235            4.5
 ii)       100 KVA                  260                 1760              4.5
 iii)      200 KVA                  500                 3000              5.0
 iv)       315 KVA                  580                 4200              5.0
 v)        500 KVA                  850                 5800              5.0


4.1           Insulatio n mater i al and cle arances :-

(a)           Materials :- Elec trical grade in sul ation craf t paper of
              triveni Ballarpur o r       equivalent mak e subject to appro val
              of     the   Engineer - in-charge.   P ress   board   of   Sena pat y,
              whitel y of Ra ma n ma ke or e quivale n t subject to app ro val
              of Engineer -in-ch arge Per mawoo d or Haldiwood blo cks
              shall be use d f or top and bott o m yo k e insulatio n.
(b)           Radial clearance o f LV coil to core (bare conductor) sh all
              not be less the m :-
              i)       63 KVA             -           3.5 MM.
              ii)      100 KVA            -           4.0 MM.
              iii)     200 KVA            -           4.0 MM.
              iv)      315 KVA            -           4.5 MM.
              v)       500 KVA            -           5.0 MM.


(c)     Radial clearance b etween HV & LV s hall not be less than 11 mm
        f or ratings 25 KV A to 315 KVA an d 12 mm f or 500 K V A.
(d)     Phase to phase clearance between HV conductor sha ll not be
        less than 10 mm w ith the mini mu m of 2 x 1 mm p res sboard t o
        cover the ro ds.
                                        TS 8
(e)    The mini mu m elec trical clearance b e tween the win ding an bod y
       of the tank (between inside surf ace of the tank and outside edge
       to the wind ings) s h ould be 30 mm.
(f )   Mini mu m end ins u lation to ear th shal l be 26 mm.
(g)    No. of c oils HV/p h ase ( mini mu m)

          i.   For 63 & 100 KV A        -      4 Nos.
         ii.   For 200 & 315 K V A      -      6 Nos.
        iii.   For 500 KVA              -      8 Nos.

(h)    Thickness of locking spacers b etween HV coil s -10 mm
       (mi ni mu m)
(i)    No. of axial wedg es between L V an d HV wind ing eq uispaced
       around LV-6 f or 6 3 KV A , 8 f or 100 & 200 KVA & 1 2 f or 315 &
       500 KVA.
(j)    Mini mu m external clearances of Bush ing ter mina ls :
                    Phase to Phase      Phase to earth
       HV           255 mm                 140 mm
       LV           75 mm                  40 mm

5.0            TANK     :-   The   t ransf ormers   ta nk   shall   be   of   robust
               constructio n and s hall be b uilt of ele ctricall y we lded M .S.
               plates. All join ts o f tank and f ittings shall be oil tight a nd
               no bulging shall occur during serv ice. The tank des ign
               shall be such tha t the core a nd w i ndings can b e lif ted
               f reel y. The tank p late shall be of such streng t h that the
               co mplete tra nsf ormer when f illed with oil ma y be l if ted
               bodil y b y mean s o f the lif ting lugs provided. Tank ins ide
               shall be paint ed with var nish/zin c chro mate. Top co ver
               shall be slig htl y sl opic (dif f erence of heights sho uld be 20
               mm + 10 %) towa r ds H.V. Bushin g and cover the top with
               end wall s. Sh ape o f the tank s hall b e rectangul ar onl y. No
               other shap e will b e accepted. The t a nk shall be f abrica ted
               b y welding at cor nes. No Hor izonta l or vertical j oints in
               tank side an d its b otto m or t op cover will be allo wed.
(a)    (I)     Side wall p late thi ckness     :      3.15 mm u pto 10 0 KVA
                                               :      4.0 mm A bove 10 0 KVA
                                       TS 9
      (II)   Top and bo ttom pl ate thicknes s:     5.00 mm u pto 10 0 KVA
                                              :     6.0 mm ab ove 100 KVA
(b)          Reinf orced b y wel ded angle of size 50 x 50 x 6 mm on all
             the outside walls on the edge of tank to f orm two e qual
             co mpart me nts. On e f ace of reinf orceme nt angle shoul d be
             continuous welde d with th e tank su rf ace such that o t her
             side of the angl e f orms invert ed "L". The per ma nent
             def lection is not mo re than 5 mm u p to 750 mm lengt h &
             6 mm up -to 125 0 mm length, wh en transf or mers t ank
             without oil is su bjected to a vacuu m of 760 mm. of
             mer cur y.
(c)          Lifting lug s :- 2 Nos. welded h eav y du t y lif ting lugs of
             M.S. plate 8 mm. Thick suitabl y r einf orced b y ve rti cal
             supporting the wel ded edgewi se belo w the lug on the s ide
             wall, up -t o the re inf orcing angle, f or transf or mers u p to
             100 KV A ratin g. For transf or mers of 200 K VA rat ing a nd
             above No. of such lugs shoul d be 4.
(d)          Pulling Lug: - 4 N os. of welded heav y d ut y pul ling lu gs of
             M.S. plates of 8 mm thi ck shall be pr ovided on widt h si de
             pull the tra nsf orme rs horizonta ll y.
(e)          Top cover Gasket & Bolts:
      (1)       The Gasket provid ed in between Top Cover Plate and
                Tank sha ll be of 5 mm. An d 6 mm thick Neopr ene
                Rubbersed Co rk sh eet conf irming to IS :4352, Part - II
                f or ratings up t o 100 KVA a nd above 100 K V A
                respectivel y.
      (2)       G.I. Nut Bolts sh all be of size 3/8" x 1.5" with one
                plain and one sprin g washer suita bl y s paced to press the
                cover f or ratings 'u p -to 100 KVA. For ratings above 100
                KVA GI Nut Bo lt s of 1/2" dia with one plate washer
                shall be use d f or top cover f ixing spa ced at 4" a part.
                                        TS 10
        (3)        The height of the tank shall be su ch that the c lear
                   height up to the T op Cover Pl ate of 120 mm is ac hieve d
                   in Top Yo ke in c ase of transf ormer s up to 1 00 KV A.
                   The above cleara n ce, is achieved f ro m th e top mos t -liv e
                   part of the tap changer in case of transf ormers abo ve
                   100.
6.0     (a)        Heat diss ipation b y tank walls e xcluding top a nd
                   botto m sh ould be - 500 W/ m 2 .
        (b)        Heat Diss ipation b y f in t yp e radiat or o f 1.25 mm t hick
                   sheet wil l be work ed out on the basi s of ma nuf actures
                   data sheet. Tend ered should sub mit the calculation
                   sheet.
        (c)        For 63 a nd 10 0 KVA Tra nsf ormer , 2 Nos. Radiat ors
                   shall be prov ided onl y on LV Side a nd shall be of f in
                   t yp e. The y sh ould be f ixed at right angle to the si des
                   and not origina ll y. For transf ormers above 100 KVA ,
                   radiators shall be provided on both sides.
        (d)        Arrange men t f or studs pr ovided f or f ixing of HV
                   bushings shou ld be in diamon d shap e so that the arcing
                   horns are p ositione d verticall y.
7.0                Total Minimu m O i l Volume : -
S.            KVA Rati ng     Oil in Lit ers (incl usive      Per missibl e Oil
No.                           of oil abs orbed i n core      absorptio n (Ltrs .)
                                  coil Asse mbly)
  i)            63 KVA                   150                           6
 ii)           100 KVA                   190                           7
 iii)          200 KVA                   400                          15
 iv)           315 KVA                   500                          19
 v)            500 KVA                   700                          26


Note :-            It the abso rption o f oil in core and w inding As se mbl y is
mo re than per mis sible value, f irst f illing of oil volume should b e
                                         TS 11
increased accord i ngl y. Detail calc ulation of absorption should be
sub mitted.


8.0   Conservator :

      (a)             The total volume of conservator shall be such as it contains 10%
              quantity of the oil. Normally 3% quantity of total oil will be contained
              in the conservator. Dimension of the conservator shall be indicated on
              General arrangement drawing.

      (b)             Die cast oil level indicator shall be provided on the side which
              will be with fully covered detachable flange with gasket and tightened
              with M.S. Nut Bolt and will be fixed on the side of rating plate and
              drain value.

      (c)             The pipe from conservator tank connecting to main tank shall be
              of 30mm internal dia and shall have a slopping plate so that the oil
              falling from the pipe shall not fall directly on the active job and shall
              fall on the sidewalls only. The plat should project in the conservator so
              that its end is approximately 20 mm above the bottom of the
              conservator. Thus slopping plate should be fitted such that the clearance
              from yoke/live part of the tap changer is maintained as prescribed i.e.
              120 mm.

      (d)             The conservator shall be provided with the drain plug and a
              filling hole, with cover. In addition, the cover of the main tank shall be
              provided with an air release plug.

9.0   Breather : Breather joints will be screwed type. It shall have die-Cast
                  Aluminum body. Make of breathers shall be subject to Engineer-in-
                  charge's approval. Volume of breather shall be suitable for 500 gms.
                  of silica gel for transformers up-to 200 KVA and 1 Kg for
                  transformer above 200 KVA.
10.0 Terminals :
                                               TS 12


       (a)               Brass rods 12 mm dia for H.T. & L.T. with necessary nuts, check
                         nuts and plain thick brass washers for rations up-to 100 KVA.




       (b)               For ratings above 100 KVA :
                   (1)      Brass rods 12 mm dia. for H.T. with necessary nuts, check nuts
                            and plain thick brass washers for rating up-to 100 KVA.
                   (2)      Tinned copper rods for L.T. 20 mm dia for 200 and 315 KVA,
                            and 30 mm dia for 500 KVA , transformers with necessary nuts,
                            check nuts and plain thick tinned washers.

       (c)               H.T./L.T. bimetallic connectors shall be prodded with transformers
                         up to 100 KVA rating.

11.0                     Bushings :
             (I)         For 11 KV-12 KV Bushing will be used and for 433 volts 1.1 KV
                         terminal bushing will be used, Bushings of the same voltage class
                         shall be interchangeable. Bushings with plain shall as per IS-3347
                         shall be mounted on side of the tank and not the top cover. Only
                         continuous sheet metal pocket shall be provided for mounting of all
                         H.V./L.V. Bushings and the same shall not be fixed on pipes. Sheet
                         metal pocket shall be design in such a way that all HT. Bushings
                         shall remain parallel equidistance all through and inside connections
                         of winding bushing shall remain within the pocket. Bushings having
                         duly tested as per IS-3347 shall only be acceptable.
             (II)        Internal Connections :- In case of HV winding all jumpers from
                         windings to bushing shall have cross section than the winding
                         conductor. For copper winding. Joint shall be made by using silver
                         brazing alloy. For Aluminum winding joints shall be made of
                         Alkapee Aluminum brazing rods with suitable flux will be made
                         and alternatively joints will be made by using tubular copper rods
                         properly crimped at three spots. Aluminum brazing , rods to be used
                                          TS 13
                 ring formed on other end and nut bolting an HV bushing stud. L.T.
                 Star connection will be made by using Aluminum/Copper Flat and
                 properly brazed or bolted with crimped lugs on winding by means
                 of plain or spring washers and lock nuts to the flat. Other end of the
                 conductor     of   the    conductor      is   brazed   on   "L"   shape
                 Aluminum/Copper flat and flat nut bolted with neutral bushing
                 Stud. ALTERNATIVELLY, for 63 KVA and 100 KVA ratings, all
                 the three terminals of LV windings together with terminal for
                 neutral bushing shall be properly brazed and then covered with
                 Aluminum tubular sleeve of suitable length and cross sectional area
                 duly crimped in order to provide sufficient strength to the joint. The
                 star connection should be wrapped with cotton/paper tap.


                         Firm Connection for LV winding to bushings shall be made
                 by adequate size of "L" shape flats nut bolted with LV Bushing
                 stud.

                         SRBP tube/insulation paper should be used for delta
                 connection and on the portion of HV winding joining to HV
                 bushing.


12.0 Rulers :- For Transformers of rating 200 KV and above four Nos. rollers of
                  150 mm diameter and 50 mm width , shall be provided.

13.0 Tank Base Channel :

     To be fitted across the length of the transformer.

        (I)              For 63 and 100 KVA Transformers - Two channels of 75
                 mm X 40 mm.
        (II)             For 200 & 315 KVA Transformers - Two channels of 100
                 mm X 50 mm.For 500 KVA Transformers - Two channels of 125
                 mm X 65 mm.
                                            TS 14




14.0 Terminal Marking plates and Katia Plates :-


               The transformers shall be provided with a plate showing the relative
      physical position of the terminal and their markings. The transformers shall
      provided with non detachable rating plate of Aluminum anodized material fitted
      in a visible position furnishing the information's , as specified in IS:2026. The
      rating plate shall be embossed/engraved type but not such printing. The relative
      position of tapping switch and corresponding voltages may also be shown on
      the rating plate.

15.0 Fittings :- The fittings on the transformers shall be as under :


      (I)          Rating and diagram plate         -    1 No.

      (II)         Earthing terminals with lugs     -    2 No.

      (III)        Lifting lugs 8mm thick           -    2 Nos. upto 100

                                                         KVA and 4 Nos.

                                                         above 100 KVA

      (IV)         Oil filling hole with cap on conservator - 1 No.

      (V)         Drain cum sampling value - 20mm. Dia for transformer :- up-to 100
                  KVA and 32 mm for 200 KVA and above (It shall be covered with
                  metallic cover by pot welding)

      (VI)         Conservator with drain plug      -    1 No.
      (VII)        Thermometer pocket               -    1 No.
      (VIII)       Aluminum die cast Silica gal -        1 No.
                  dehydrating breather (500 gms.
                  Capacity up-to 200 KVA and
                                   TS 15
         1000 gms. For 315 & 500 KVA)




(IX)       Platform mounting channel         -        2 Nos.
         (with hole suitable for axle of
         roller for transformers of 200 KVA and above rating)


(X)        Die cast Oil level gauge indicating three
         Position of oil marked as below :
         Minimum             (-)    50 C
                                    300 C
         Maximum                    980 C


(XI)       Bushings :

         With brass stem and metal parts for :

         H.T.                       3 Nos.

         L.T.                                4 Nos.

         Each bushing should be provided with 3 Nos. of brass nuts and 2 pair

         be washers for connecting terminals.


(XII)      Radiator                 -        Details shall be given as per

                                             Drawing ( to be provided only

                                             on L.V. side up-to 100 KVA.


(XIII)   Arcing horn for H.T. bushings       6 Nos.


(XIV)    Pulling lugs 8 mm thick             4 Nos.
                                             TS 16
       (XV)         Metallic cover spot welded to tank for drain value shall be
                   provided.

       (XVI)        Explosion vent in case of transformers of - 1 No.

                 200 KVA and above

       (XVII)       Uni- directional Rollers for 200 KVA            -        4 Nos.

                   And above (150 mm dia and 50 mm wide)

       (XVIII)      Filter value - 32 dia for 200 KVA and -         1 No.

                   above

       (XIX)        Off circuit tap changing switch with indicator handle and locking
                   device with tap ranging from (+) 3% to (-) 9% in steps of 3%on HV
                   side for HV variation. Direction of rotation marked.

       (XX)         Top cover lifting lugs           -     2 Nos.

       (XXI)        Bimetallic connectors

                   HV                                      -        3 Nos.

                   LV                                      -        4 Nos.

16.0          TRANSFORMER OIL :- The transformer shall be supplied completed
              with first filling of oil and the same shall comply with IS : 335 - 1983 with
              latest version thereof and ageing Annexure - VI. Type tests certificate of
              oil being used shall be produced at the time of inspection.


17.0          Finishing :-

              The exterior of the transformer and other ferrous fittings shall be
              thoroughly cleaned , scraped and given primary coat and the two finishing
              coats of durable oil and weather resistant paint of enamel. The colour of
              the finishing coats shall be DARK GREEN conforming to IS : 5 of 1961
                                           TS 17
          (colours for ready mixed paints) with conservator painted with white
          colour.

18.0 Test & Certificates :-


          The following routine tests and type tests are required to be carried out the
          transformers.


     A)      Routine Tests :- Before dispatch each of completely assembled
             transformer shall be subjected at the manufactures works to following
             routine tests in accordance with the details specified in IS : 2026.


            a) Measurement of winding resistance.

            b) Ratio, polarity and phase relationships.

            c) Impedance voltage.

            d) No load losses and no load currant.

            e) Load losses.

            f)    Insulation resistance.

            g) Separate source voltage withstands.

            h) Induced over voltage with stand.

            i)    Air pressure test.

            j)    Vacuum test.




     B)      Type Test :- The following type tests shall be done transformers : - (a to
             j) as indicated under routine tests.
     C)      Lighting impulse tests :-

             m)     Temperature rise test.
                                                 TS 18
               n)       Short circuit tests.

               o)       Unplaced current tests. The value of zero sequence current in the

                        star winding shall not be more than two percent of the full load

                        current.

               p)       Pressure and vacuum test : tank shall be fixed with a dummy

                        cover with all fittings including bushings in position and shall be

                        subjected to following pressure/vacuum creedal inside the tank :

                       (a)         O.B Kg./Cm sq. above atmospheric pressure for

                                   30 minutes.

                       (b)         A vacuum corresponding to (-) 0.7 Kg./cm. sq.

                                   for 30 minutes.

       Permanent deflection of flat plat, after pressure has been released, shall not

exceed the values given below :-

       Length of place                                   Deflection

       Upto 750 mm                                       5 mm

       751 to 125 mm                                     6 mm

       1251 to 1750                                      8 mm


19.0         The type test certificates for the transformers shall be submitted with the
             tender.
             Further, the suppliers may carefully note our following specific
             requirements of short circuits, impulse voltage and temperature rise rest:


       (a)    Short circuit test and impulse voltage Tests: The NVDA intents to
              procure transformers designed and successfully tested for short circuit
              and impulse test. In case the transformers proposed for supply against the
                                     TS 19
        order are not exactly as per the tested design, the supplier shall require, to
        carry out the short circuit test and impulse voltage test at their own cost
        in the presence of the representative of the NVDA. The supply shall be
        accepted only after such test is done successfully, as it confirms on
        successful withstand of short circuit and healthiness of the active parts
        thereafter on un-tanking after a short circuit test. Apart from dynamic
        ability test, the transformers shall also be required to withstand thermal
        ability test or thermal withstand ability will have to be established by way
        of calculations.


(b)     It may also be noted that the NVDA reserve the right to conduct short
        circuit test and impulse voltage test in accordance with the ISS, airesh on
        each ordered ration at NVDA cost , even if the transformers of the same
        rating and similar design are already tested. This test shall be capple out
        on a transformer to be selected by the NVDA either at their works when
        they are offered in a lot for supply or rand sample units from the supplies
        already made to NVDA A Stores. The findings and conclusions of these
        tests shall be binding on the supplier.


        In case the transformer does not pass in either at up tests and if the active
part details are not found to be line with the design tested and approved. The
following unit measures shall be taken :


 (I)        For transformers already supplied , the guarantee period shall stand
           twice the normal guarantee period incorporated in the and the period
           of performance Security Deposit shall be suitably extend to cover the
           extended guarantee period.


 (II)       Further, supply of balance quantity of transformers will not be
           accepted by the board, till another transformer from the manufactured
           batch is satisfactorily tested (OR transformers are modified according
           to the tested design, for both tests at your cost and consequent to this
                                                  TS 20
                       if there is any delay in executing the order , the same shall be to your
                       account. Board reserves the right to take action as per terms and
                       conditions of the order.

        (c)         Temperature rise test : hear run test shall have to be conducted at
                    suppliers cost on one transformer of each rating in any offered lot during
                    the course of supplies. In case of transformers with tap, test shall be
                    conducted on the lowest tap.

                            To facilitate conduction of heat run test on any unit in any lot at
                    any point of time during the supplies, the manufactures will provide a
                    thermometer pocket which-gets immersed in oil on the side of the
                    transformer in all the transformers. This pocket shall also be used for
                    connection thermal sensing device to monitor the variations in
                    temperature and whenever required to operate the protective devices. The
                    sensor pocket shall be of 12 mm diameter with blanking screwed cap,
                    removal at site , the depth of the projecting stem of this pocket inside the
                    transformer will be below oil level. It shall not infninge with electrical
                    clearance nor obstruct the untanking of the active part.

(c)                 Transformer shall be subjected to test for over fluxing of core, wherever
                    required by the Engineer-in-charge

            (d)      TEST FOR SPILL CURRENT IN NEUTAL : :
                     The test will comprise of measuring current be shorted secondary
                     phases and neutral on applied impedance voltage at primary. The value
                     shall not exceed 2% of full load current.


20.               Acceptance Test : The following tests shall be Wiscassed by the purchase/
            Reoresentartive at the firms :-

      (1)         All the routine tests as mentioned in 18 (A) above shall be performed on
                  minimum 10% quantity of acceptance test.
                                          TS 21
   (2)      Heat run test - One unit of the ordered quantity.

   (3)      Verification of active parts on one unit of such of ordered quantity along
            with weighment of unit.

   (4)      Further, the purchaser's Inspector reserves the right to get the Spill Current
            Measurement Test and also the pressure test performed on any tank during
            their inspection.


21.0     Testing Facilities :- The tender should have adequate testing facilities for all
         routine and acceptance tests and also arrangement for measurement of losses ,
         resistance etc.

22.0     Inspection :-
   (a)      To ensure about the quality of transformers, the inspection shall be carried
            out by the Engineer-in-charge representative following two stages :-

   (1)         Where raw material is received, and the assembly is in process in the
               shop floor.

   (2)         At finished stage i.e. transformers are fully assembled and are ready for
               dispatch.

   (b)      After the main raw-materials i.e. core and coil materials and tank are

            arranged and transformers are taken for production on shop floor and a few

            assembly have been completed, the firm shall intimate the O/o Engineer-in-

            charge in this regard , So that a team of officers for carrying out such

            inspection could be deputed, as far as possible within seven days from the

            date of intimation. During the stage inspection a few assembled core shall

            be dismantled to ensure that the CRGO laminations used are of good

            quality. Further, as and when the transformers are ready for dispatch, an
                                      TS 22
      offer intimating about the readiness of transformers , for final inspection for

      carrying out tests as per relevant, I.S.S. and as in clause 20 above, shall be

      sent by the firm along with Routine Test Certificates. The inspection shall

      normally be arranged by the Engineer-in-charge at the earliest after receipt

      of offer for per-delivery inspection.


(c)   In case of any defect/defective workmanship observed any stage by the

      Engineer-in-charge inspecting officer, the same shall pointed out to the firm

      in writing for taking remedial measurement Further processing should only

      be done after clearance the inspection officer/this office.


(d)   All tests and inspection shall be carried out at place of manufacture unless

      otherwise specifically agreed up-to the manufacture and purchaser at the

      time of purchase. Manufacturer shall offer the inspector representing the

      purchaser all reasonable facilities, without charges. To satisfy him the

      material is being supplied in accordance with the specification. This will

      include stage inspection out manufacturing stage as well as Active part

      inspection during Acceptance Tests.



(e)   Random sample checking and testing of the transformer selected at random

      from the supplies made to the site shall be done for verification of technical

      details, design and losses as per approved G.T.P., drawings and technical

      specification of the order. In case of variations, the lot shall be rejected.
                                           TS 23
   (f)      The purchaser has all the rights to conduct the test including type tests, at

            his own cost by an independent agency whenever there is dispute regarding

            the quality of supply or interpretation of test results. In the event of failure

            of transformers in such tests, the expenses incurred in testing shall be to the

            supplier's account as already mentioned above in case of random testing.


23.0     Inspection & Testing of Transformer Oil :



                 To ascertain the quality of the transformer oil, the original

            manufacturer's tests report should be submitted at the time of inspection.

            Also arrangements should be made for testing of transformer oil, after

            taking out the sample from the manufactured transformers and tested in the

            presence of purchaser's representative.


24.0     Test reports on the analysis of raw materials :


                The suppler shall furnish details of source (s) of raw-materials , test

         certificates and report on the analysis of electrolytic copper/Aluminum used

         for the winding and the steel used for core, insulation material and also other

         bought out items from sub-suppliers.


25.0     Drawings :-


                The General Arrangement dimensional drawing and core coil Assembly

         drawing showing internal construction , of each transformer shall be submitted
                                           TS 24
         with the tender, Guaranteed and other Technical particulars of the transformers

         should also be submitted in A-4 size for our approval.




                                   ANNEXURE - V
                  QUALITY ASSURANCE : INSECTION ON
                                  TRANSFORMERS


1.01      To ensure about the quality of transformers, the inspection shall be carried out

          by the Engineer-in-charge representative at following two stage :-


   (1)        Where raw material is received, and the assembly is in process on the shop
              floor.

   (2)        At finished stage i.e. transformers are fully assemble and the are ready for
              dispatch.

1.02      After the main raw-materials i.e. core and coil materials and tanks are

          arranged and transformers are taken for productions on shop floor and floor

          and a few assembly have been completed, the firm shall intimate the O/o

          Engineer-in-charge in this regard , so that a team of officers for carrying out

          such inspection could be deputed. As far as possible within fifteen days from

          the date of intimation. During the stage inspection a few assembled core shall

          be dismantled to ensure that the CRGO laminations used are of good quality

          and manufacturing is confirmed in line with approved Guaranteed Technical

          Particulars/Drawings.
                                         TS 25
1.03   A quantity of more than 100 Nos. shall not be entertained for stage

       inspection. Further, the stages inspection shall be carried out in case:-

         (a)    at least 25% quantity offered has been tanked , and

         (b)    core coil assembly of further at least 30% of the quantity offered has
                been completed.

1.04   In case of any defect/defective workmanship observed at any stage by the
       Engineer-in-charge Inspecting officer, the same shall be pointed out to the
       firm in writing for taking remedial measures. Further processing should only
       be done after clearance from the Inspecting officer/this office.


1.05   Quantity offered for stage inspection should be offered for final inspection in
       full within 15 days from the date of issue of clearance for stage inspection
       otherwise stage inspection already cleared shall be liable for cancellation.


1.06   The constructional details of the transformer as per GTP shall be verified
       during the stage inspection.


1.07   As and when the transformers are ready for dispatch, an offer intimating
       about the readiness of transformers for carrying out pre-despatch inspection
       as per relevant I.S.S. and as in clause-20 of Annexure-IV , shall be sent by the
       firm. The inspection shall normally be arranged by the Engineer-in-charge at
       the earliest after receipt of offer for pre-delivery inspection.



1.08   During the pre-dispatch inspection, the routine tests , heat run test on one
       unit/rating against the order, pressure & vacuum tests as per I.S. 1180 & 2026
       shall be carried out at the works of the firm on randomly selected
       transformers in presence of Engineer-in-charge representative. The report
       shall be prepared in the proforma prescribed by this office.
                                             TS 26
1.09    Further, one unit of each rating offered shall be dismantled at the time of pre-
        dispatch inspection for physical verification for the constructional details. The
        report of pre-dispatch inspection is to be prepared in the prescribed proforma.


              Please ensure that reports of stage inspection and pre-dispatch
       inspection are prepared strictly in the prescribed proforma and no detail is left
       blank. Incomplete report may cause delay in supply of transformers which
       shall be to the supplier's account.
                                              TS 27


                                        ANNEXURE - VI
            GUARANTEED TECHNICAL PARTICULARS OF EHV
                                          GRADE OIL


S.                          Characteristics                        Requirement
No.

A.    NEW OIL
1.    Flash Point Pen sky Marten (Closed)                  140C
2.    Neutralisation value
      (a)    Total acidity, Max.                           0.03 mg KDH/g
      (b)    Inorganic acidity/alkalinity                  Nil
3.    Corrosive Sculpture                                  Non corrosive
4.    Electric Strength (breakdown voltage)Min
      (a)    New unfiltered oil                            30 KV (rms)
      (b)    New oil after filtration                      60 KV (rms)
5.    Dielectric dissipation factor                        0.002
      (tan delta) at 900C
6.    Specific resistance (resistively)
      (a)    at 900 C Min.                                 35 X 1012 ohm-cm
      (b)    at 270 C Min.                                 1500X1012 ohm-cm
7.    Oxidation stability
      (a)    Neutralization value after                    0.40 mg KOH/g
             oxidation, Max.
      (b)    Total sludge after oxidation Max.             0.10% by weight
      (c)    S.K. Value                                    4% to 8%
8.    AGEING CHARACTERSTICS
      Ageing characteristics after accelerated
      Ageing (open breaker method with copper catalyst.)
                                             TS 28


     a)   Specific resistance (resistivity)
          i) at 270 C                  2.5 X 1012    Ohm-cm (Min)
          ii) at 900 C                 0.2 X 1012          Ohm-cm (Min)
     b)   Dielectric dissipation factor.             0.20 Max.
          (Tan Delta)
     c)   Total acidity in mg KOH/g                  0.05 Max.
     d)   Total sludge value                         0.05 by weight


B)   CHARACTERISTIECS OF OIL IN THE TRANSFORMER.
     The important characteristics of the
     Transformer oil after it is filled in
     The transformer (within 3 months of
     filling) shall or as follows :-
1.   Electric strength (breakdown voltage)                 40 KV (Min)
2.   Dielectric dissipation factor Tan.                    0.01 (Max)
     Delta at 900 C
3.   Specific resistance (Resistively)                     10 X 1012 Ohm-cm
     at 270 C Ohm-cm.)
4.   Flash point . P.M. (closed)                           1400 C (Min)
5.   Interfacial tension at 270 C                          0.03 N/m (Min)
6.   Neutralization Value (total acidity)            0.05 mg KH/g
7.   Water content                                         35 PPM (Max)
                                         TS 29

                                ANNEXURE - VI
                  TECHNICAL SPECIFICATION FOR
                 THREE PHASE 33/11 KV STEP DOWN
                         POWER TRANSFORMERS



1.                   SCOPE :- The specification covers the design, manufacture
           testing and inspection before dispatch and delivery at places anywhere in
           M.P. of the transformers listed in Annexure-III.
                  The specification covers oil immersed. Naturally air cooled (type
           on). Outdoor type. Three phase. 50 Hz, 33/11 KV step down power
           transformers of capacities 1 , 6 , 3.15 & 5.0 MVA.


2.                   APPLICABLE STANDARDS :-

     (a)        Unless otherwise modified in the specification. The transformers
           shall comply with the requirement of ISS : 2026 (latest issue) and REC
           specification 1978 and ISS : 3347 (latest issue). The bushings used shall
           conform to ISS : 2099 (latest issue) except as modified herein.)

     (b)        Type : - The transformers shall be double wound. Three phase oil
           immersed, oil natural cooled (type On Core type suitable for out door
           installation in tropical climate and shall be insulated with DPC insulation
           on HV & LV windings should be of temperature class as per the
           temperature rise stipulated in this specification.
                                         TS 30
            Climatic Conditions.

 i)      Peak outdoor temperature                     : 500 C
 ii)     Maximum oil temperature attainable           : (500 C + 500 C) 1000 C under
                                                         max. Temperature max. Load
                                                         condition.


 iii)    Maximum relative humidity                    : 75 % (sometime approaches
                                                         saturation point)
 iv)     Minimum relative humidity                    : 10 %
 v)      Average No. of thunderstorm days per         : 40 days
         annum
 vi)     Average number of rainy days per             : 90 days
         annum
 vii)    Number of months of tropical monsoon         : 3 months
         conditions
 viii)   Average annual rainfall                      : 125 cm
 ix)     Wind pressure                                : 100 Kg/m2
 x)      Altitudes not exceeding                      : 1000 metes.

(c)              Design and Standardization :-

  i.        The transformers and accessories shall be designed to facilitate operation.

             Inspection maintenance and repairs :- All apparatus shall also be

             designed to ensure satisfactory operation under such sudden variations of

             load and voltage as may be met with under working conditions on the

             system, including those due to short circuits.

 ii.        The design shall incorporate every reasonable precaution and provision

             for the safety of all those concerned in the operation and maintenance of
                                    TS 31
       the equipment keeping in view the requirement of Indian Electricity

       Rules.

iii.   All material including bought out items like bushing, oil, radiators,

       conductor and insulating materials used shall be of the best quality and of

       the class most suitable for working under the conditions specified and

       shall withstand the variation of temperature and atmospheric conditions

       without undue distortion or deterioration on or setting up of undue

       stresses in any part and also without affecting the strength and suitability

       of the various parts for the work which they have to perform.


iv.    Corresponding parts liable to replacement shall be interchangeable.

 v.    Cast iron shall not be used for chambers of oil filled apparatus or for any

       part of the equipment which is in tension or subject to impact, stresses or

       where corrosion due to acidity or sludging is likely to occur. This clause

       is not intended to prohibit the use of suitable grades of cast iron for parts

       where service experience has shown it to be satisfactory e.g. large value

       bodies.


vi.    All outdoor apparatus, including bushing insulators with their mounting

       shall be designed so as to avoid external pockets in which water can

       collect and internally air could trap.


vii.   All taper pins used in any mechanism shall be of the split type complying

       with IS : 2593 for these items.
                                              TS 32
viii.             All connections and contacts shall be of ample section and surface for

                  carrying continuously the specified currents without heating and fixed

                  connection shall be secured by bolts or set screw of common size

                  adequately locked against vibration. Lock-nuts shall be used on stud

                  connections carrying current.


 ix.              All apparatus shall be designed to minimize the risk of accidental short

                  circuit caused by animals, birds or vermin.


3.           STANDARD RATINGS :- The standard ratings shall be 1600 KVA 3150

             KVA and 5000 KVA with off circuit taps.


4.           CONTINUOUS MAXIMUM RATING AND TEMPERATURE RISE :- The

             transformers shall have a continuous maximum rating at the specified normal

             ratio, frequency and temperature rise.


        A)      All transformers shall be capable of operation continuously in accordance

                with IS loading guide at their continuous maximum rating and at any ratio

                without exceeding temperature rise.


        B)      Transformers with tapping ranges extending more than 5 % below normal

                voltage shall meet the temperature rise limits specified in IS : 2026 on all

                tapings on which the rated current is not more than 95% of the maximum

                rated current in lowest voltage tapping. On other tapings, they shall operate

                continuously without injurious heating. The loading of the transformers is
                                               TS 33
                 to be in accordance with IS : 6600 - guide for loading of oil immersed

                 transformers natural cooled units.


     C)          The transformers shall be capable of operation without danger on any

                 particular tapping at the rated voltage in KV provided that the voltage does

                 not very by more than +/- 10% of the voltage corresponding to the tapping.

                         The maximum temperature rise in each transformer where tested at
                 its continuous maximum rating shall not exceed the following limit at the
                 reference ambient air temperature of 500 C


          i)         Temperature of oil by thermometer        :     500 C
          ii)        Temperature of winding by test           :     550 C
                     resistance.

5.        NO LOAD VOLTAGE RATIO :- The no load voltage ratio corresponding to
          the principal tapping by 33 , 000/11,000 volts.

6.        OIL :- Transformer oil be used for first filling shall comply with the
          specification hereunder. Generally as per IS : 335-1972 (Third revision) &
          REC specification No. 39/1985 except in so far as values indicated separately
          as per Board's specification for EHV Grade Oil.
A)        NEW OIL
i)        The important characteristics of new oil shall be as follows.
S.No.                               Description                           Technical particulars
1.              Flash point pen sky marten (closed) Min.            1400 C
2.              Neutralization Value
                a)    Total acidity, Max.                           0.03 mg KOH/9
                b)    Inorganic acidity/alkalinity                  Nil
3.              Corrosive Sculpture                                 Non-corrosive
4.              Electric Strength (breakdown voltage)Min.
                                                    TS 34
                a)    New unfiltered oil                                 30 KV (rms)
                b)    New oil after filtration                           60 KV (rms)
5.              Dielectric dissioation factor                            0.002
                (tan delta) at 900 C (Max)
6.              Specific resistance (resistivity)
                a)    at 900 C Min.                                      35 X 1012 Ohm-cm
                b)    at 270 C Min.                                      1500X1012 Ohm-cm
7.              Oxidation stability
                a)    Neutralization value after                         0.40 mg KOH/g
                      Oxidation. Max.
                b)    Total Sludge at the oxidation Max.                 0.10% by weight
                c)    S.K.value                                          4 % to 8 %


S.No.           Description                                              Technical Particulars
     (1)        AGEING CHARACTERSTICS
                Ageing characteristics after accelerated
                Ageing (open breaker method with copper)

           a)     Specific resistance (resistivity)
                  i) at 270 C              2.5 X 1012       Ohm-cm (Min)
                  ii) at 900 C             0.2 X 1012             Ohm-cm (Min)
           b)     Dielectric dissipation factor.            0.20 Max.
                  (Tan Delta)at 900 C (Max)
           c)     Total acidity in mg KOH/g                 0.05 Max.KOH/g
           d)     Total sludge value (Max)                  0.05 by weight


B)         CHARACTERISTIECS OF OIL IN THE TRANSFORMER.


           The important characteristics of the Transformer oil after it is filled in
           The transformer (within 3 months of filling) shall or as follows :-
                                                 TS 35
        S. Characteristics                                            Specification
 No.


1.          Electric strength (breakdown voltage)             40 KV (Min)
2.          Dielectric dissipation factor Tan.                0.01 (Max)
            Delta at 900 C
3.          Specific resistance (Resistivity)                 10 X 1012 Ohm-cm
            at 270 C.)
4.          Flash point . P.M. (closed) (Min)                 1400 C (Min)
5.          Interfacial tension at 270 C                      0.03 N/m (Min)
6.          Neutralization Value (total acidity) (Max)        0.05 mg KH/g
7.          Water content PPM (Max)                           35 PPM (Max)



5.          TAPS :-

7.1              Off-circuit tap transformers shall have taps ranging from + 3% to - 9% in
                 steps of 3% each on HV. Winding for HV. Variation to give normal 11 KV
                 on LV side.

(e)              Nut, bolts and washers which may have to be removed for maintenance
                 purposes shall receive minimum of one coat of paint after erection.

(f)              The spacing of the bolt center on the tank and its cover should be so
                 designed that the gaskets when pressed after bolting leave no room for
                 either ingress of moisture of leakage of oil during transportation or normal
                 service or full load and guaranteed temperature rise conditions.

12.              CORE
                 The Cores shall be constructed from high grade cold rolled no ageing grain
                 oriented silicon steel laminations.


      (I)        MAGENTIC CIRCUIT
      (A)          The design of the magnetic circuit shall be such as to avoid static
                   discharges, development of short circuit paths within itself or of the earth
                                     TS 36
        clamoring structure and the production of flux components at right
        angles to the plane of the lamination which may cause local heating.

(B)     Every care shall be exercised in selection, treatment and handling of core
        steel to ensure that so far as practicable from distortion, burrs or sharp
        edge.

(C)     Although the oxide/silicate coating given on the core steel is generally
        adequate, laminations can be insulated by the manufactures if considered
        necessary.

(D)     Oil ducts shall be provided wherever necessary to ensure adequate
        cooling and efficient heat transfer. The winding structure and major
        insulation shall not obstruct the free flow of oil through such ducts nor
        permit local hot spots. Where the magnetic circuit is divided into pockets
        by cooling ducts parallel to the planes of the lamination or by insulating
        material above 0.25 mm thick tinned copper strip bridging places shall be
        inserted to maintain electrical continuity conductivity between pockets.

(E)     The frame work and clamping arrangement shall be earthed in
        accordance with clause -16 (II) of this Technical specification.

(II)   Construction of cores

(A)      All parts of the cores shall be of rodust design capable of withstanding
         any shocks to which they may be subjected to during lifting , transport ,
         installation and service.
(B)      All steel sections used for supporting the core shall be thoroughly sand
         blasted and shot blasted after cutting , drilling and welding.

(C)      Adequate provision shall be made to prevent movement of the core and
         winding relative to the tank during transport and installation or while in
         service.
                                             TS 37
  (D)          The supporting framework of the cores shall be so designed as to avoid
               the pressure of pockets which would prevent complete emptying of the
               tank through the drain value or cause trappings of air during oil filling.

13.            TERMINAL ARRANGEMENT

13.1           The transformers shall be fitted with shaded porcelain bushings of
               outdoor type suitable for solder less connectors on HV as well as LV
               side. The HV/LV bushing shall not be provided with arcing horns,
               Aluminum bushing stems and aluminum metal parts will not be
               accepted.


13.2           The bushings shall be filled with transformer oil, EHV grade, which
               shall be of non oil communicating type with small aperture of 2 mm
               diameter.


               The HV/LV bushings shall have the characteristics as per IS : 2099
               (latest issue). The electrical characteristics of bushing insulators shall be
               in accordance with IS : 2099 AS AMENDED FROM TIME TO TIME.
               All type and routing tests shall be carried out in accordance with IS :
               2099-1973. The test voltages for various tests as stipulated in IS : 2099 -
               1973 are reproduced below :-
 Nominal        Rated Voltage         Visible          One minute       Lightning impulse
  System        of the Bushing     discharge test      wet & dry          with stand test
  Voltage                                            withstand test     (Imduise Voltage)
      KV             KV                 KV                 KV                   KV
       11             12                 9                 35                   75
       33             36                 27                75                   170


13.3        Dimension of the LV 12 KV bushings including the neutral (11 KV side)
            shall conform to IS : 3347 ( PART - III and those of the 36 KV bushing (33
            KV side shall conform to IS : 3347 (PART-V)
                                      TS 38


14.    VIBRATION AND NOISE


       Every care shall be taken to ensure that the design and manufacture no all
       transformers and accessories shall be such as to reduce noise and vibration
       to the level obtained in good modern practice.
                 The manufacture will ensure that the noise level shall not be
       more than 3 Db above the IEEMA standard duplication TRAI.


15.    FLUXDENSITY : OVER FLUXING

(A)    Over fluxing of the core shall be limited to 12.5%

(B)    However, in case of transformers with variable flux , the voltage variation
       which would effect flux density at every tab shall be kept in view while
       designing the transformers.


16.    INTERNAL ERTHING ARRANGEMENT

(I)    General :- All metal parts of the transformer with the exception of the
       individual core laminations. Core bolts and associated individual clamping
       plates shall be maintained at some fixed potential.


(II)   Earthing of core clamping structure :- The top main core clamping structure
       shall be connected to the tank body by a copper strip. The bottom clamping
       structure shall be earthed by one or more of the following methods.


(A)    By connection through vertical tie rods to the top structure.


(B)    By direct metal to metal contact with the tank base maintained by the
       weight of the core and the windings.


(C)    By a connection to the top structures on the same side of the core as the
       main earth connection to the tank.
                                        TS 39
(III)   Earthing of magnetic circuit.


(A)     The magnetic circuit shall be earthed to the clamping structure at one point
        only through a disconnect able link placed in an accessible position beneath
        an inspection opening in the tank core. The connection to the link shall be
        on the same side of that core and the main earth connection.


(B)     Magnetic circuits having as insulated sectional construction shall be
        provided with separate link for each individual section. When oil ducts or
        insulating barriers parallel to the plane of the laminations divide one
        magnetic circuit into two or more electrically separate parts, the ducts on
        barriers shall be bridged in accordance with clause-12 (1) and the magnetic
        circuit shall not be regarded as being of sectional construction.


(IV)    Size of ear thing connections


                  All ear thing connections with the exception of those from the
        individual cell clamping rings shall have a cross sectional area of not less
        than 0.8 Sq. Mm. Connections inserted between laminations of different
        section of core as per clause - 16 (III) B shall have a cross sectional area of
        not less than 0.2 Sq.mm.


(V)     Lead from winding to bushing and inter cake connection: - The leads from
        winding to bushing and inter cake connection should be rigid enough to
        withstand normal vibration and transportation shocks and short circuit
        stresses. They should be spaced in such a way that necessary clearances are
        maintained not only in air but with oil medium at the lowest permissive
        electrical strength as per relevant ISS over the period of normal service.
17.     CLEARANCE ELECTRICAL

              Voltage          Medium           Clearance Phase to   Clearance Phase to earth
                                                      Phase
               11000             Air                 255 mm                 205 mm
               33000             Air                 350 mm                 320 mm
                                    TS 40


18.   PARALLEL OPERATION
      The transformers of the same service voltage shall be suitable for parallel
      operation, the load being shared in proportion to the capacities and
      percentage impedance volts which will be within that specified in the ISS.


19.   OVER LOAD CAPACITY
(A)   Each transformer shall be capable of carrying sustained over loads as
      stated in ISS : 6600


(B)   Type of load : The transformer will supply a mixed power and lighting
      load with varying power factor from 0.6 lag to 0.8 lead due to capacitors.

20.   GUARANTEE

      The manufacturer shall among other things guarantee the following.

(1)   Quality and strength of material used. Both electrical and mechanical.

(2)   Satisfactory operation during the guarantee period of 24 month from the
      date receipt at stores. This period will be reckoned from the day all
      accessories are received enabling assembly testing, commissioning and
      commercial operation of transformers.

(3)   Performance figures are to be supplied by tenderer in the schedule of
      guaranteed particulars. In schedule of GURANTEED TECHNICAL
      PARTICULARS. all details as required in IS : 2026 shall be given.

21.   TOLERANCE

      The tolerance of guaranteed performance figures shall be as specific in the
      clause 11.1. as per latest version of IS : 2026.
                                      TS 41
22.     WHELLS AND AXLES

        The transformers of 5000 KVA rating shall be provided with flanged
        wheels suitable for use on a 1435 mm. Gauge track. These wheels shall be
        suitable for being turned through an angle of 900C and locked in that
        position when the tank is jacked up. Other transformer shall be provided
        with bi-directional flat roller suitable for use on a 1000mm. Gauge track.

23.     FITTINGS & ACCESSORIES

        Unless other wise specified in the order, the following standard fitting as
        detailed in Annexure - VI attached shall be provided. The fittings shall be
        in accordance with the details to the extent these are specified in IS : 2026.

      (i)       Inspection cover

      (ii)      Rating plate.

      (iii)     Diagram plate with tap position and relative HV/LV voltage

      (iv)      Two ear thing terminals.

      (v)       Lifting lugs.

      (vi)      4 jacking pads

      (vii)     Conservator with top filled cap and bottom drain value.

      (viii)    Dehydrating breather of required sizes.

      (ix)      Connecting pipe with value and Buchholz relay.

      (x)       Radiator with top air release plug and connected values and
                bottom for connection to main tank.

      (xi)      HV      -        3 bushings

      (xii)     LV      -        4 bushings

      (xiii)    Off circuit tap switch with lock and 2 keys.

      (xiv)     Mercury thermometer.

      (xv)      Thermometer (dial type) with one contact for alarm.
                                       TS 42
       (xvi)     Thermometer pocket.

       (xvii)    Magnetic oil level gauge indicating three position of oil marked as
                 follows :

                 Minimum        -       (- 5 deg. C) :       (30 deg C)

                 Maximum        -       (98 deg. C)

       (xviii)   Oil filling hole and tap.,

       (xix)     Air release device on tank tap.

       (xx)      Pressure relief device through explosion vent diaphragm with
                 fresh equalizer pipe air release plug.

       (xxi)     Gas and oil actuated relay.

       (xxii)    2 filter values (top value , lower value to be used also as drain
                 value )



24.    TESTS AND INSPECTION



24.1   Type test :- the purchaser intends to procure transformers designed and

       successfully tested for short circuit and impulse test, which may be carefully

       noted by the tenderer. The transformers to be supplied should have been

       subjected to all the type tests in accordance with IS : 2026 , Further, The

       transformer should have also passed the Pressure test in accordance with

       Appendix-II (A). Type test reports for bought out equipments shall be

       furnished by the supplier after obtaining from the manufacture of

       equipments. Wherever needed by the Purchase. The type test reports

       including short circuit withstand test report and lightning impulse test report

       must accompany the offer. The short circuit withstand test report must

       accompany the active part general arrangement drawings duly attested and

       certified by testing agency. In case the tenderer proposed to carry out type
                                       TS 43
       tests in near future, the expenses to be incurred towards the test shall be to

       their account. The report of ERDA for loss Measurement report if conducted

       on offered transformer shall be furnished.


24.2   Routing Test : The following tests in addition to those listed in IS 2026
       shall continue for routine tests. These tests are required to be carried out by
       the supplier on each and every unit manufactured by them. Oil leakage test
       as detailed in Appendix-II "B" of this tender.
        (i)       Di-electric test on transformer oil.
        (ii)      Checking for pre-shrinkages - Appendix - II "B"
        (iii)     Spill current in neutral - Appendix - II "B"
        (iv)      Measurement of magnetizing current at low voltage.

24.3   Acceptance Test : - The following tests shall be witnessed by the
       Purchaser/Representative at the firm's works :-
1.     All the routine tests as mentioned in 24.2 on each and every offered
       transformer.
2.     Heat run test - One unit of the ordered quantity.
3.     Verification of active parts on one unit of each rating of ordered quantity
       along with weighment of unit.
4.     Further, the Purchaser's Inspector reserves the right to get the Spill Current
       Measurement Teat (App. II "B") and also the Pressure. Test (App.IIA)
       performed on any tank during their inspection.

24.4   Inspection :- All tests and inspection shall be carried out at the place of
       manufacture unless otherwise specifically agreed upon by the manufacturer
       and Purchaser at the time of purchase. The manufacturer shall offer the
       Inspector representing the Purchaser all reasonable facilities without charges
       to satisfy him that the material is being supplied in accordance with this
       specification. This will include stage Inspection during manufacturing stage
       as well as Active Part Inspection during Acceptance Tests.
                                           TS 44
            The Purchaser has all the rights to conduct the test including type test. at his
            own cost by an independent agency whenever there is dispute regarding the
            quality of supply or interpretation of test results. in the event of failure of
            transformers in such tests, the expenses incurred in testing and cost of
            transformer etc. Shall be to the Supplier's account.

25.   TEST REPORTS ON THE ANALYSIS OF RAW MATERIALS :
      The tenderer shall indicate the source (s) of raw materials (s) called for in
      schedule-v and enclose test certificates and report on the analysis of
      electrolytic copper used for the winding and the steel used for core insulation
      material as also bought but items from suppliers.

26.   GUARANTEE             AND      PERNALTY         FOR     LOSSES       OF     POWER
      TRANSFORMERS CAPITALISATION OF TRANSFORMER LOSSES.


      (a) The no load losses in kilo watts at rated voltage and rated frequency and
      the total losses in kilo watts at rated full load current and rated frequency at
      750 C shall be guaranteed for the purpose of quality computations. The test
      figures of the no load and the load losses will be compared with the
      corresponding guaranteed figures.

      (b) The penalties shall be separately evaluated from :

      (1)       The excess of the test figures of the no load loss in KW over the
                corresponding guaranteed value and.


      (2)       The excess of the test figures of the load losses in KW over the
                corresponding guaranteed value.
                No tolerance shall be permitted over the guaranteed figures for
                computation of penalty.

      (c)       The penalties shall be calculated at the rate of Rs. 1,52,685.00 per KV
                for the of no load loss and at the rate of Rs. 65960.00 per KW for the
                excess of load losses. For fraction of the penalties shall be applied on
                                  TS 45
      prorata basis. If the test figures of the losses are less than the guaranteed
      values. No bonus will be allowed.

(d)   The tenderers must clearly specify whether the losses quoted are FIRM

      or subject to is tolerance. In case of any ambiguity. Loading as per is

      tolerances shall be considered for purpose.


(e)   The power transformers in cash rating with lowest losses would be

      given preference.

      While the tenderers may offer their own design It may be noted that the

      transformer losses at 750 C should not exceed the following limit.


      S.No.         Rating         No load loss (fixed     Load losses at 750C
                                        losses) (KW)              (KW)
      1.        1600 KVA          3.0                      16.0
      2.        3150 KVA          3.5                      20.0
      3.        5000 KVA          5.0                      30.0


(f)   As mentioned in (E) above, the power transformers in each rating with

      the lowest, losses would be given preference. For fair comparison offers,

      it is essential that the tenderers should quote FIRM losses. No load and

      load losses quoted by the firm shall be capitalised for comparison of

      prices as per formula indicated in the tender.


(g)   The purchaser reserves the right to reject are transformer, if during tests

      at supplier's works, the tested no load losses and load losses. Exceed the

      corresponding maximum guaranteed losses by more then the following

      values.
                                  TS 46
Total losses                :      10% of the total guaranteed
                                   losses
Component losses            :      15% of each component losses
                                   provided that the tolerance for
                                   for total losses of 10% of not
                                   exceeded.

(h)    The purchaser reserves the right to test any one transformer from the

       each lot offered for inspection/supplied in any independence laboratory

       of national repute for the purpose of testing the no load and load losses.

       The entire expenses for the same shall be borne by the firm and results

       obtained shall be considered and applicable in all the supplies.


(i)    The supplier shall provide along with the tender. design details of core

       assembly showing the constructional details, core diameter, net/gross

       sectional area of the core assembly etc. The information must also be

       given in respect of votes per turn at principal tap for normal voltage.

       The loss curves for type/grade of steel laminations being used for core

       shall also be provided along with the tender document.
                                               TS 47


                                        APPENDIX - I

        A conservator complete with sump and drain valves shall be provided in such a
position so as not to obstruct the electrical connections of the transformer having a
capacity between highest and lowest visible levels to meet the requirement of
expansion of the total oil volume in the transformer and cooling equipment from the
minimum ambient temperature and the cooling equipment from the minimum ambient
temperature of (-) 300C to 950C. The minimum indicated oil level shall be with the
feed pipe from the tank covered with not less than 15mm depth of oil and the
indicated range of oil level shall be minimum to maximum.

(ii)     If the sump is formed by extending the feed pipe in inside the conservator,
         this extension shall be for at least 25 mm.

(iii)    One oil gauge magnetic type with provision for low levels alarm shall be
         mounted on conservator to indicated the minimum normal and maximum
         level as given below :


        Minimum                 (-)    50 C
        Normal                         300 C
        Maximum                        980 C

(iv)     One end flange of the conservator shall be bolted into position so that it can
         be removed for cleaning purpose.


(v)      The oil connection from transformer tank to the conservator vessel shall be
         arranged at a rising angle of 3 to 9 to the horizontal upto gas and oil actuated
         relay.


(vi)     Each conservator vessel shall be bitted which a breather in which silica gel is
         the dehydrating agent and designed so that.

         a)       The passage of air is through silica gel.
                                        TS 48
      b)    The external atmosphere is continuously in contract with silica gel.

      c)    The moisture absorption indicated by a change in colour of the tinted
            crystals can be observed from distance.

      d)    Breathers shall be mounted at approximately 1400 mm. above ground
            level.

2.   Pressure relief devices :

            A safety valve of the chimney type with an equalizer pipe
     interconnecting the top of the conservator and upper most part of the safety
     valve shall be provided to prevent rise of oil in the safety value pipe. A stop
     cork should also be provided in the interconnecting pipe. An air release cork
     shall also be fitted in convenient position.

            The safety valve pipe shall preferably take off the side of the
     transformer thank near to the tank cover and not from the top of the tank cover.
     This is with a view to prevent the gases forming in the tank from rising into the
     safety valve pipe and thereby passing the gas and oil actuated relay (defeating
     its purpose) and for avoiding the necessity for providing a bottom diaphragm
     for the safety valve pipe which would be necessary in case it takes off from the
     tank cover.
                                    TS 49
                             APPENDIX - ii (A)

(A)   Pressure test :-

             One transformer tank of each size shall be subjected to a pressure
      corresponding to twice the normal head of oil or to the normal pressure plus
      35 KN/M (51b sq.in) whichever is lower measured at the base of the tank
      and will be maintained for one hour. The permanent deflection of flat
      plates, after the excess pressure has been released shall not exceed the
      figure specified below.


         Horizontal length of flat Plate (in       Permanent deflection (in
                          mm.)                              mm.)

       up to and including 750                 5
             751     to     1250               6.5
            1251     to     1750               8
            1751     to     2000               9.5
            2001     to     2250               11
            2251     to     2500               12.5
            2501     to     3000               16
          Above      3000                      19
                                    TS 50
                             APPENDIX - II (B)

(B)   Oil leakage test :-

                 All tanks and oil filled compartments shall be tested for oil
      tightness by being completely filled with air/oil of a viscosity not greater
      than that of insulating oil conforming to IS : 335 at an ambient temperature
      and subjected to a pressure equal to the normal pressure pls 35 KN/m2 (51
      b/Sq. in) measured at the base of the tank. This pressure shall be maintained
      for a period not less than 10 minutes during which time no leakage shall
      occur.

      Checking for press shrinkages :- The transformer will be dried out for 16
      hours at temperature between 80 to 1000 C. The active parts shall be
      tightened and height of assembled unit shall be measured. The difference
      between two measurements shall not be less than two percent as compared
      to height measured at normal temperature.

      Spill current in neutral :- The test will comprise of measuring current
      between shorted secondary phases and neutral on applying impedance
      voltage at primary winding. The value should not exceed 2% of full load
      current.
                                              TS 51


26.    Earthing :
                     General : The object of an ear thing system is to provide is nearly
as possible a system of conductors at a uniform potential and as nearly zero or
absolute earth potential as possible. The purpose of this is to ensure that in general all
parts of apparatus other than live parts shall be at earth potential as well as to ensure
that persons coming in contact with it shall be at earth potential at all times.

                     System ear thing: Ear thing associated with current carrying
conductor is normally essential to the security of the system and is generally known
as system ear thing.

                     Equipment ear thing : Earthing of non - current carrying metal
work and conductor is essential to the safety of human life, of animals and of
property and is generally known as equipment earthing.
                     As far as possible all earth connections shall be visible for
inspection and shall be carefully made; if they are poorly made or inadequate the
purpose for which they are intended, loss of life and property or serious personal
injury may result. Earthing shall conform to the follow specifications. For other
details not covered in this specification IS : 3043 - 1987 shall be referred to.

             Type of Earth Electrodes :

             (a)     Pipe Earth electrode.
             (b)     Plate earth Electrode.
             (c)     Strip or conductor earth electrode.

             Selection of earth electrode :
                     G.I. pipe or G.I. plate earth Electrode shall be used except where it
is unavoidable to use copper plate earth electrode due to corrosive soil conditions for
direct current system or for large capacity substations.
                     Strip or conductor electrode is recommended for hard and rocky
soils and in locations where there are limitations to the use of pipe or plate earth
electrode.
                                        TS 52
                  Where the soil is highly corrosive, the earth electrode, shall be of
copper. Where soil contains sulphur, copper electrode shall be adequately tinned.


          Arrangement for earth electrode :
                  Pipe earth electrode : G.I. pipe shall be of medium class , 38/40
mm dia and 2.50 meters in length. Galvanizing of pipe shall conform to relevant
Indian Standards. G.I. pipe electrodes shall be cut tapered at the bottom and provided
with holes of 12 mm. dia drilled not less than 7.5 cm from each other up to 2m of
length from bottom. The electrode shall be buried in the ground vertically with its top
not less than 20 cm. below ground level (details shown in fig. 1)




NOTE : THREE OR FOUR BUCKETS OF WATER TO BE POURED INTO SUMP
           EVERY FEW DAYS TO KEEP THE SOIL SURROUNDING , THE
           EARTH PIPE PERMANENTLY MOIST.


Fig. 1 TYPICAL ILLUSTRATION OF PIPE EARTH ELECTRODE
                                        TS 53


                   Pipe earth Electrode: For plate electrodes minimum dimensions of
the electrode shall be as under :-
          (a)      G.I. Plate Electrode - 60cm. x 60 cm. 6.3 mm. thick.
          (b)      Copper plate Electrode - 60 cm X 60 cm. X 3.15 mm. thick.
                       The electrode shall be buried in ground with its faces vertical
and top not less than 1.5m below ground level (details shown in the figure 2).




NOTE : THREE OR FOUR BUCKETS OF WATER TO BE POURED INTO SUMP
           EVERY FEW DAY'S TO KEEP THE SOIL SURROUNDING , THE
           EARTH PLATE PERMANENTLY MOIST.


Fig. 2     TYPICAL ILLUSTRATION OF PLEATE EARTH ELECTRODE
                                          TS 54


          Strip or conductor electrode:


           (a)    Strip electrodes shall not be less than 25 mm x 4mm. of galvanised
                  iron and 25 mm x 1.6 mm of copper. For conductor electrode the
                  size of round conductor shall be not less than 6 SWG of G.I. and 8
                  SWG of copper.
           (b)    The length of buried strip or conductor earth electrode shall be not
                  less than 1.5 m. This conductor length shall be increased if
                  necessary on the basis of the information available about soil
                  resistance, so that required earth resistance is obtained.
           (c)    The electrode shall be buried not less than 0.5m. deep , in a trench
                  either single straight or circular or in a number of trenches radiating
                  from single point.
           (d)    If conditions necessitate use of more than one strip or conductor
                  electrode, they shall be laid either in parallel trenches or in radial
                  trenches.


           Method of installing watering arrangement :


                  In the case of plate earth electrodes a watering pipe of 50mm. dia of
medium class G.I. pipe may be provided and attached to the electrode. A funnel with
mesh shall be provided on the top of this pipe for watering the earth. In case of pipe
electrode a 40mm x 20 mm reducer shall be used for fixing the funnel. The watering
funnel attachment shall be housed in masonry enclosure of not less than 30cm x 30cm
x 30cm.
                  A cast iron/M.S. frame with cover having locking arrangement shall
be suitably embedded in the masonry enclosure, or a cover of R.C.C. slab of size
33.8cm x 33.8 cm and thickness 38 to 40 mm be provided.
                                           TS 55
          Location of earth electrode :


                  Normally an earth electrode shall not be situated less than 1.5 m.
from any building. Care shall be taken that excavations for earth electrode may not
affect the column footings or foundation of the building, in such cases electrode may
be further away from the building.


                  The location of the earth electrode will be such where the soil has
reasonable chance of remaining moist, as far as possible. Entrances, pavements and
road ways, are definitely avoided for locating the earth electrode.




          Artificial treatment of soil :

                  In case there is no option of site and earth electrode resistance is
high, the earth electrode resistance shall be reduced by artificial chemical treatment of
the soil. For this purpose, the most commonly used substances are sodium chloride
(common salt). calcium chloride, sodium carbonate, copper sulphate and salt mixed
with soft coke or charcoal in suitable proportion. But before any chemical treatment is
applied, possible corrosive effect on the electrode material and connections must be
taken into consideration. When this treatment is resorted to, the electrode shall be
surrounded by charcoal/coke and salt as indicated in fig. 1 & 2 , This treatment of soil
shall be specified in the schedule of work and in such cases, excavation for earth
electrode shall be as per dimensions indicated in fig. 1 & 2.

          Size of earthing lead :

                  Main earthing lead : The main earthing lead shall be of G.I. wire or
G.I. strip in the case of G.I. pipe earth electrode and G.I. plate earth electrode and
copper wire or copper strip in the case of copper earth electrode. For all electrical
installations except sub stations and generating station, the earthing lead shall be not
less than one half of the sectional area of that of the largest conductor to be protected
but that a conductor larger than 100 sq. mm nominal cross sectional area in case of
                                         TS 56
copper conductor and 150 sq. mm. in case of G.I. conductor need not be used. The
minimum size of main earthing lead shall not be less than 8 SWG of copper or G.I.
wire and 20 mm x 2mm in case of copper strip or 25 mm x 3 mm in case of G.I. strip.


          Size of earth continuity conductor :

                  The nominal minimum cross sectional area of an earth continuity
conductor not contained within a cable or flexible cord shall be 14 SWG copper or 12
SWG of G.I.


          Method of connecting earthing lead to earth electrode:


                  The earthing lead should be connected to the earth electrode by
means of lugs soldered or crimped.
                  In the case of plate earth electrode the earthing lead shall be
securely bolted to the plate with two bolts, nuts checknuts and washers. In the case of
pipe earth electrode, it shall be connected by means of a through bolt, nuts and
washers, Alternatively the G.I. strip may be clamped near the top end of the G.I. pipe
electrode the strip being dished suitably at the end portion coming in contact with the
G.I. pipe and earth lead lug shall be securely bolted to this strip with two bolts, nuts,
check nuts and washers.


                  All materials used for connecting the earth lead with electrode shall
be of G.I. in case of G.I. pipes and G.I. plate earth electrodes and of tinned brass in
case of copper plate electrode.

                  The earthing lead shall be securely connected at the other end to the
earth suds provided on the main board/SDBS by means of soldering and lags.

                  Loop earthing shall be provided for all mountings of main board
and other metal plate switches and distribution fuse boards with not less than 14 SWG
copper or 12 SWG G.I. or 4 sq.mm. aluminum wire.
                                          TS 57



          Protection of earthing Lead:

                   The earthing lead from electrode onwards shall be suitably
protected form mechanical injury by a 15 mm. dia. G.I. pipe in case of wire and by 40
mm. dia. medium class G.I. pipe in case of strip. Portion of this protection pipe within
ground shall be buried at least 30cm. deep (to be increased to 60cm. in case of road
crossing and pavements). The portion shall be recessed in walls and floors to adequate
depth.

Number of earth electrodes in Medium voltage Installations:

          In medium voltage installations, where there are a number of motors or
other equipments to be earthed at least a minimum of 2 number earth electrodes.
(Inter connected with an earth bus) should be provided for earthing of equipment. The
number of electrodes has to be increased if lower earth circuit impedance is required.
The distance between two electrodes shall not be less than twice the length of the
electrodes. The earth resistance of any single earth electrode should not normally
exceed 5 ohms. The earth resistances of a number of rods or pipes connected together
in parallel is practically proportional to the reciprocals to the number of electrodes
used.

Equipment and portions of installations which shall be earthed :

Except for equipment provided with double insulation, all the non-current carrying
metal parts of the installation are to be earthed properly. All metal conduits trunking,
cable sheaths switch gears, distribution fuse boards , lighting fittings and other parts
made of metal shall be bonded tighter and connected by means of two separate and
distinct conductors to an efficient earth electrode.

                   Earthing of metallic parts shall not be affected through any
structural metal work which houses the installation. Where metallic parts of the
installation are not required to be earthed and liable to become alive should the
insulation of the conductors become defective, such metallic parts shall be separated
by durable non conducting material from any structural work .
                                         TS 58
                  The relevant portions of the Indian Electricity Rules i.e. Rules 32 ,
51, 61, 67, 69, 88 (2) and 90 shall apply.

           Earth circuit impedance:


                  In installations where the apparatus is protected by fuses the total
earth circuit impedance shall not be more than that obtained by the following graph
given in fig. 3




           Fig .3 Recommended Earth Circuit Impedance


           Painting :

           Painting work in general :

           Paints: Paints, oils, varnishes, etc, of approved make in original tin to the
satisfaction of the Engineer-in-Charge shall only be used.
           Preparation of the surface: The surface shall be thoroughly cleaned and
dusted, before painting is stared. The proposed surface shall be inspected by the
Engineer-in-charge or his authorized agent and shall have received the approval
before painting is commenced.
                                            TS 59
          Application : Paint shall be applied with the brush. The paint shall be
spread as smooth and even as possible. Particular care should be paid to rivets, nuts,
bolts & every lapping. Before drying out, it shall be continuously stirred in the smaller
containers with a smooth stick while it is being applied.
                   Each coat shall be allowed to dry out sufficiently before a
subsequent coat is applied.
          Scope : Painting on old surface in indoor situations will not include primer
coat except where specially mentioned in the schedule of work or special specification
However. Where rust has formed on iron and steel surfaces. The spots shall be painted
with one and rust primer coat.

          Precautions : All furniture, fixtures , glazing , floors, etc. shall be protected
by covering. All stains, smears, splashings, dropping of every kind shall be removed.
While painting of wiring etc., it shall be ensured that painting of wall and ceiling etc.,
is not spoiled in any way.

          Painting of wiring on wood batten : The wiring shall after creation be
neatly painted with two coats of oil less non-cracking paint of suitable colour to match
the surroundings to the satisfaction of the Engineer-in-charge.

          Painting of conduit and accessories : After installation all accessible
surface of conduit pipes, fittings, switch and regulator boxes, etc, shall be painted
with two coats of approved enamel paints or aluminum paint as required to match the
finish of surrounding wall, trusses, etc.

          Testing of Installations :

          General : On completion of installations the following tests shall be carried
out :-

          1.       Insulation Resistance Test.
          2.       Polarity Test of Switch.
          3.       Earth Continuity Test.
          4.       Earth Electrode Resistance Test.
                                           TS 60
           Insulation resistance:

                  Insulation resistance shall be measured by applying between earth
and the whole system of conductors or any section thereof with all fuses in place and
all switchs closed , and except in earthed concentric wiring all lamps in position or
both poles of the installation otherwise electrically connected together , a direct
current pressure of not less than twice the working pressure provided that it need not
exceed 500 volts for medium voltage circuits. Where the supply is derived from a
poly phase A.C. system. The neutral pole of which is connected to earth either direct
or through added resistance, the working pressure shall be deemed to be that which is
maintained between the phase conductor and the neutral.

                  The insulation resistance shall also be measured between all
conductors connected to one pole or phase conductor of the supply and all the
conductors connected to the neutral or to the other pole or phase conductor of the
supply with all lamps in position and switches in "Off" position and its value shall be
not less than that specified in para 32.

                  The insulation resistance in Mega ohms measured as above shall
not be less than 50 mega ohms divided by the number of outlets or when PVC
insulated cables are used for wiring 12.5 mega ohms divided by the number of
outlets.
                  Where a whole installations is being tested, lower value than that
given by the formula, subject to a minimum of I mega ohm is acceptable.

                  A preliminary and similar test may be made before lamps etc., are
installed and in this event the insulation resistance to earth should be not less than
100 mega ohms divided by the number of outlets or PVC insulated cables are used
for wiring 25 mega ohms divided by number of outlets.

                  The term "outlet" includes every point along with every switch
except that a switch combined with a socket outlet, appliance or light fitting is
regarded as one outlet.
                                         TS 61


                  Control rheostats, heating and power appliances and electric signs
may , if required, be disconnected from the circuit during the test, but in that event
the insulation resistance between the case or frame work; and all live parts of each
rheostat, appliance and sign, shall be not less than that specified in the relevant Indian
Standard Specification or, where there is no such specification, shall be not less than
half mega ohm.

          Polarity Test of Switch.

                  In a two wire installation a test shall be made to verify that all
switches in every circuit have been fitted in the same conductor throughout and such
conductor shall be labeled or marked for connection to the phase conductor or to the
non-earthed conductor of the supply.

                  In a three wire or a four wire installation a test shall be made to
verify that every non-linked single pole switch is fitted in a conductor which is
labeled or marked for connection to one of the phase conductor of the supply.

                  The installation shall be connected to the supply for testing. The
terminals of all the switches shall be tested by a test lamp, one lead of which is
connected to the earth Glowing of the test lamp of its full brilliance, when the switch
is "on" position irrespective of appliance in position or not, shall indicate that the
switch is connected to the right polarity.

Testing of earth continuity path:-

                     The earth continuity conductor including metal conduits and
metallic envelops of cables in all cases shall be tested for electrical continuity and the
electrical resistance of the same along with the earthing lead but excluding any added
resistance or earth leakage circuit breaker measured form the connection with the
earth electrode to any point in the earth continuity conductor in the completed
installation shall not exceed one ohm.
                                              TS 62


       Measurement of earth electrode resistance :

               The auxiliary earth electrodes, besides the test electrode, are placed at
suitable distance from test electrode (see fig. 4). A measured current is passed between
the electrode "A" to be tested and an auxiliary current electrode "C" and potential
difference between the electrode "A" and auxiliary electrode "B" is measured. The
resistance of the test electrode "A" is then given by
                                    V
                             R = ----------
                                    I
       Where
               R - Resistance of the test electrode in ohms.
               V - Reading of the voltmeter in volts.
               I - Reading of the ammeter in amps.




             Fig. - 4 Method of measurement of earth Electrode Resistance


       (a)     Stray current flowing in the soil may produce serious errors in the
               measurement of earth resistance. To eliminate this, hand driven
               generator is used.
       (b)     If the frequency of the supply of hand driven generator coincides with
               the frequency of stray current there will be wandering of instruments
               pointer. An increasing or decrease of generator speed will cause this to
               disappear.
                                          TS 63


              At the time of test, the test electrode shall be separated from the earthing
system.
              The auxiliary electrode shall be of 13mm diameter mild steel rod driven
upto 1 meter into the ground.
              All the three electrode shall be so placed that they will be independent
of the resistance area of each other. If the test electrode is in the form of rod, pipe or
plate, the auxiliary current electrode "C" shall be placed at least 30 meter away from it
and the auxiliary potential electrode "B" shall be placed midway between them.
              Unless three consecutive readings of test electrode resistance agree the
test shall be repeated by increasing the distance between electrodes A and C upto 50
meters and each time placing the electrode B midway between them.
              On these principles "Megger Earth Tester" containing a direct reading
ohm meter a hand driven generator and auxiliary electrodes are manufactured for
direct reading of earth resistance of electrodes.


Furnishing of certificate : On completion of an electric installation (or an extension
to an installation) a certificate shall be furnished by the agency executing the work
countersigned by the Engineer-in-charge under whose direct supervision the
installation was carried out. This certificate shall be the prescribed form in addition to
the test certificate required by the M.P.E.B.


29.    OVERHEAD LINE WORK :

       Scope : This specification covers the requirement for the installation testing
and commissioning of overhead distribution lines up to and including 11 KV service
connection and street lighting work and the materials used therein.
       Materials :
       Supports :
              Supports for overhead lines and for street light shall be any of the
following types or as specified by Engineer-in-charge and shall be of adequate
strength conforming in all respect to Rule 76 of Indian Electricity Rules.
                                            TS 64
       (a)    Steel tubular poles : This shall conform to I.S. 2713-1964. This shall be
seem less/swaged and welded type as specified and shall be in three stepped sections.
Unless otherwise specified 1/6th of the length of the pole plus 15 cm from its base
shall be coated with black bituminous paint both internally and externally. The
remaining portion of the pole shall be painted with one coat of red oxide on its
external surface. The pole shall be complete with a cap and base plate.
       (b)    Steel-rail poles : This shall conform to standard specification of Indian
Railway. Since the 22, 25 and 45 Kg ( 40,50 and 60 LBS.) rails do not have adequate
strength in the longitudinal direction, longitudinal guys should be provided at every
tenth pole in a straight run.
       (c)    Cement concrete poles :         Reinforced cement concrete (RCC) and
prestressed cement concrete (PCC) pole shall conform to I.S. 785-1964 and I.S.
1678- 1960 respectively and shall carry an earth bond in accordance with Rule 90 of
LE Rules. The dimensions shall be as per design conforming to the load requirement.
Particulars of four typical designs of RCC poles are given in table - 5 to this part.
Concrete poles shall be treated with suitable chemicals like silicon for the portion to
be buried in ground where sub-soil water is high and acidic as in costal areas.
       (d)    Wood poles : This shall conform to I.S. 876-1970. This shall be of teak,
sal or any other hard wood. The dimension shall be as per design conforming to load
requirements. It shall be straight with a deviation tolerance of 5 cm. on the entire
length of pole. The pole is tapered shall taper uniformly from bottom to top. The
surface of the pole shall be smooth all knots being trimmed close. The pole shall be
free from the saps or hollows, cross breaks, dead streaks and reasonably free form
decay, split or checks hollow heart, rot ring sake, insect damage, knots, scares etc.
The butt end of the pole shall be trimmed flat perpendicularly to its length. All
wooden poles shall be properly treated with ASCU wood preservative or creosote.
The standard pole can be made out of 18 SWG GI Sheet may be provided where so
specified as a precaution against adverse weather.
       (e)    Galvanized Iron (G.I.) pipes mild steel pipes (both seem less or ERW)
fabricated poles of structural steel and another special type of poles for garden light /
low height street light may also be used.
                                          TS 65
30.     Line Materials
Cross arms : The following sizes of cross arms shall be used :
        (a) For 11 K.V. lines: V cross-arms of width 920 mm. between the V arms
made of channel iron 75mm x 40 mm. x 5.7 kg./ meter.
        (b) For low tension lines:
              (i) For 3 phase 4 wire lines for aluminum conductors of size 3 of 7/3.4
mm. and I of 7/2.79 mm. :-
              Two numbers 75mm X75mmX 6mm 610 mm. long angle iron single
phase cross arms arranged one below the other for the dead ends and 65mm x 65mm
x 6 mm 1220 mm. long angle iron cross-arm for pin points.
              (ii) For single phase line for aluminium conductors of size up lo 7/2.44
mm.:-
              75mm x 75mm x 6mm             610mm. long angle iron for dead ends and
65mm x 65mm x 6 mm         610 mm long angle iron for pin points.
              A Minimum distance of 8 cms for LV / MV lines and 10 cms. for HT
lines shall be left from the centre of the extreme insulator pin holes to the end of
cross-arm. The spacing of the pin holes shall be as per clearances specified in para
The cross-arm shall be complete with pole clamps made of M.S. flats of size not less
than 50 mm. x 6 mm. with necessary bolts, nuts and washers. The cross arm shall
have pin holes as required. Length of cross-arms for carrying guard wires shall be
such that the guard wire shall always be not less than 30 cm. beyond the outer most
conductor of same configuration.
              "D" Iron Clamp:        Where so specified in the contract, conductor shall
be spaced vertically supported on shackle insulators which are attached to the pole by
means of "D" shaped clamps made of M.S. flats of size not less than 50 mm x 6 mm.
and galvanized. The dimension of "D" iron clamp shall be such as to hold a 75 mm
high and 90mm dia. (minimum size) shackle insulator. The "D" iron clamp shall be
complete with pole clamp with necessary bolts, nuts and washers and insulator bolt
pins.
                                         TS 66
              G.I. Strap : Where "D" iron clamps are not specified, a pair of strap
plates of galvanized iron of size 40 mm x 3 mm and length 23 cm shall be used with
shackle insulators.
              The cross arm and the pole clamp shall be treated with one coat of red
oxide primer before erection and finished with two coats of approved paint after
erection along with other hardware.
31.    Stay / strut :
              Stay : A stay set shall consists of stay rod anchor plate, bow tightener or
turned buckle thimbles, stay wire and strain insulator. The stay rod shall be with stay
grip in case turn buckle is used instead of bow tightener. The entire stay assembly
shall be galvanized. The stay wire shall be 7/3.15 mm G.I. generally conforming to
I.S. 2141-1968 grade 2 [specification for galvanized steel strand (first revision) (with
amendments No. 1 and 2)] The anchor plate shall be of M.S. galvanized and not less
then 30 cm. x 30 cm. x 6.4 mm thick and the size of stay rod shall be not less than
1.8m (6 feet) long and 19mm dia.
              Strut : A strut shall generally consists of a pole of the same section
which it supports or slightly lighter.
32.    Insulator :
              The porcelain insulator shall conform to I.S. 1455-1966 [specification
for porcelain insulator for over head power lines (below 1000 Volts) (revised) (with
amendment No. 1)]. Suitable for over head power lines with a normal voltage
greater than 1000 V. (Second revision). for over head power lines with a normal
voltage greater than 1000 V. This shall be vitreous through out and not absorbant. The
exposed surface shall be glazed. Insulator or shall have adequate mechanical strength,
high degree of resistance to electrical puncture and resistance to climatic and
atmospheric attack.
              The insulator shall be of the following types :
       (a)    Pin and shackle insulator for L.T. and M.V. Lines. Tae neutral wire
              should be attached to G.I. or aluminium knobs.
       (b)    Pin and disc type for H.V. Lines.
              The minimum size of shackle insulator shall be 90mm dia by 75mm
              high.
                                           TS 67
                 The minimum size of pin insulator shall be 65mm dia by 100 mm. high.
The pin insulator shall be suitable for 12mm cordean thread and shall be complete
with G.I. pin, nuts and washers.
33.    Conductors :
                 Conductors shall be any type of the following types or as specified by
the Engineer-in- charge.
                 (a)   All aluminium stranded: This shall comply with the requirements
                       of I.S. 398-1961.
                 (b)   Aluminium conductors steel reinforced : This shall comply with
                       the requirements of I.S. 398-1961.


                 Choice of conductors : The physical and electrical properties of
different conductors shall be in accordance with relevant Indian Standards. All
conductors shall have a breaking strength of not less than 350 kg.
                 No conductor of smaller cross - section than the following shall be used
for distribution lines.
                 All aluminium standard        -    A.C.S.R.
                 7/1.96mm                      6/2.11 mm    plus   1/2.11 mm

34     Binding materials :

                 Binding of conductors with insulators shall be done with 12 SWG soft
aluminium conductor.
                 Guard wire :
                 Guard wire shall be of G.I.
                 It shall have minimum breaking strength of 635 Kg. in accordance with
Rule 88 of Indian Electricity Rule.
                 It shall also be of sufficient current carrying capacity to ensure
rendering the line dead without risk of fusing of guard line.
35.    Lighting Arrestors :
                 These shall conform to I.S. 3070-1965 Part -I and I.S. 3070-1966 Part-II
as applicable.
                                            TS 68
                 Horn gap type :
                 This type of lighting arrester shall be used for L.T./M.V. lines wherever
specified.
                 Surge Diverters : Single pole unit enclosed in a G.I. case for outdoor
mounting shall be used for system not exceeding 650 volts.
                 Pallate Thyrite type surge diverters :
                 This types of surge diverters with standard rating of 11 KV shall be
used for H.T. Lines.
                 The lighting arrester system shall conform to Rule 92 of I.E. Rules. See
Appendix -A.

36.    Paint :
                 Paints of approved quality and shade conforming to relevant Indian
standards shall be used.
                 Primer coats shall be with red oxide ready mixed and of approved
manufacture.

37.    Routing :
                 Route : The route shall be adopted based on the following :
                 As far as possible the route of distribution line as well as the location of
stay sets shall be decided taking into consideration the present and future
requirements.
                 The route of distribution lines shall generally follow the route of roads.
                 Poles for distribution lines may be located along the side of the road, on
the road bend a little away from the road edge and drain.
                 Normally there shall be a pole located at road junction.
                 The route shall be chosen to avoid use of struts and continuous curve as
far as possible.
                 Junction of main road and service lane shall be preferred for location of
pole so that the street light will benefit the service lane as well.
                 Front of entrance to building shall be avoided for locating poles.
                                           TS 69
38.      Spacing of poles :
               This shall be in accordance with Rule 85 of Indian Electricity Rules.
               When a LV/MV line runs close to a row of buildings the neutral
conductor shall be situated at end nearest to the building of the cross arm.
               Where distribution line and street light fixtures are erected on the same
support, the span shall normally not exceed 45m.
               Span chosen shall be such that in a residential area adequate street
lighting can be provided.


39.      Clearances:
               The spacing of conductor shall comply with the requirements given
below:
               Minimum clearance between conductors on the same support.

              (a)        L.T. Lines

                    (i) Vertical configuration of conductor :-             … 30 cm
                        Minimum clearance between earth and
                        live Conductors.

                         Minimum clearance between live                    … 20 cm
                         conductors.

                    (ii) Horizontal configuration of conductor :-          … 45 cm
                         Minimum clearance between live wires
                         on either side of support.

                         Minimum clearance between live wires              … 30 cm
                         on the same side of support.

                         Minimum distance between the centre of            … 8 cm
                         insulator pin hole and end of cross-arm

              (b)        H.T. Lines (11 KV)

                         Triangular configuration :-

                         Minimum distance between the centre of            … 10 cm
                         insulator pin hole and end of cross-arm
                                        TS 70


               The conductors arc erected in such a way that they form an equilateral
pattern of side of 0.92m minimum the vertical clearance between top and bottom
conductors being 76.25 cm. ( 2 feet and 6 inches)


               The minimum clearance of the lowest conductor above ground levels
across a street, along a street and else where for different voltage system shall be in
accordance with Rule 77 of Indian Electricity Rules
               The minimum clearance of over- head lines and service lines for
different voltage system from building shall be in accordance with Rules 79 & 80 of
Indian Electricity Rules.
               When conductors of different voltages are erected on the support. Rule
81 of Indian Electricity Rules shall be adhered to. The clearance between LV/ MV
and 11 KV lines shall be not less than 1m.
               A clearance of not less than the height of the tallest support may he
maintained between the parallel over-head lines on different supports.
               When two over-head lines cross the crossing shall be made at right
angles as for as possible. The vertical clearance between LV/MV lines and 11 KV
Lines shall not be less than 1.25m.
               The minimum clearance between guard wires and LV/MV line shall be
10 cm. and between guard wire and 11KV line shall be 30 cm.
               Rule 86 and 87 of Indian Electricity Rules shall be followed for-
clearance between power and telecommunication lines and shall not be less than 1.5m
for lines upto 11 KV.          '                ,


41         Excavation for Foundation

               General :
               After the location of supports/ stays arc pegged accurately the
excavation work shall be taken up.
               Every care shall be taken to see that the pits arc not oversized while
digging.
                                            TS 71
                 Care shall be taken to see that the minimum amount of soil is distributed
to take advantage of bearing value of virgin ground.
                 The pit for supports/stay strut shall be filled up or concreted only in
presence of Engineer-in-Charge.
                 Suitable caution signs red lights and other protective measures as
directed by the Engineer-in Charge, should be provided, near the pit warning the
pedestrians/vehicular traffic till such lime the pit is back filled and surface leveled.


                 Excavation for supports:


                 The depth of pit shall be such that normally 1/6th of the length of pole is
buried in the ground. The size of the pit shall be suitable for the foundation of the
support as per clause 41.
                 The foundation pit shall be generally excavated in the direction of the
lines.
                 The position of pit shall normally be such that the stay makes as large
an angle as possible with the support. A good angle for the stay will be within the
range of 40 degrees to 60 degrees.
                 The depth of the pit shall be such that normally a length of 45 cm of
stay rod shall project above the ground level. The size of the pit shall be suitable for
the foundation of slay as per clause 41.

         Excavation for struts:


                 The pit for strut shall be located at a distance not less than 1.8m from
the pole.
                 The depth of the pit shall be such that at least 1.2 m. of the strut buried
in the ground and the size of the pit shall be suitable for the foundation of the strut as
per clause 41.
                                            TS 72


41.      Erection;
               Erection of supports:
               All supports shall be correctly aligned before concreting or the bed
filling. of the pit with excavated earth.
               All supports including RCC and PCC shall be erected over the cement
concrete 1:3:6 (1 cement : 3 coarse sand :6 graded stone aggregate of 40 mm. nominal
size) bed of 15 cm, thick either cast in situ or precast and laid in excavated pit
irrespective of the use of base plate. The area of this cement concrete bed shall be of
0.35 sqm. for steel tubular /steel rail and ether steel poles or 0.5 sqm. for RCC /PCC/
Wood Poles.
               The support shall be erected in any one of the following ways.
               (a)   Steel, tubular / steel rail / other steel pole shall be fixed in cement
concrete 1:3:6 (1 cement : 3 coarse sand : 6 graded stone aggregated of 40 mm
nominal size.) foundation with not less then 20 cm. thick layer of cement concrete all
around the support the foundation being continued up to 15 cm. above ground level
and tapered suitably into a collar.
               (b)   RCC / PCC poles shall be erected using brick or stone ballast with
excavated earth as binder which is well consolidated. The ramming shall be done in
layers of 20cm. Water as necessary shall be used during this operation. The sectional
area of the consolidated ballast foundation shall not be less then 0.5 sq.m. including
the area occupied by support itself and shall be maintained up to the ground level.

               RCC and PCC poles except where specified otherwise, do not require
any setting in concrete. No cement concrete collar is also necessary Far such type of
poles.
               (c)    Wood poles : Wood poles shall be erected in any of the above
methods as specified in the contract.
               After concreting the excavated earth shall be back filled and well
consolidated in layers of 20 cm.
                                         TS 73
              Watering of concreted foundation above ground level and curing for at
least two weeks shall be done; by using moist gunny bags etc; before loading the
pole.
              Erection of stay:
              A stay shall be provided al all angle or terminal pole.
              The stay rod will be set in position in the excavated pit.
              Correct positioning and setting of stay set is essential. The stay rod with
anchor plate shall be embedded in cement concrete 1:3:6(1 cement :3 coarse sand:6
graded stone aggregate of 40 nun. nominal size) not less than 0.28 cu.m. in content in
such a way that the top of the concrete block is well below the ground level to prevent
uprooting of the stay rod. Alternatively the stay rod shall be embedded vertically in
cement concrete 1:3:6 (1 cement : 3 coarse sand: 6 graded stone aggregate of 40 mm.
nominal size) foundation 42 cm in section the anchor plate lying over 15 cm. thick
cement concrete. The stay rod shall bent at unthreaded portion such that the stay wire
at the bent portion of stay rod arc in correct alignment. Care must be taken to avoid
sharp bend or damage to galvanization
              After concrete has set, back filling shall be done with excavated earth
and ramming in layers of 20 cm. adding water as required.
              The top surface of the concrete around the stay shall be cured by means
of moist gunny bags, etc. for at least two weeks before loading the stay.
              The stay clamps shall be located near about the center of gravity of the
pull of the overhead conductors. the stay clamps shall be galvanized.
              One end of the stay wire shall be fixed to the bow tightner or the stay
grip of the stay rod and the other end to the stay clamp fixed to the pole by means of
well spliced nuts using G.I. thimbles. A strain insulator shall be provided
approximately at the middle of the stay wire. Turn buckle when used, shall be
installed at the top of the stay wire.
              The stay shall also be connected and bonded properly to earth.
              Double stays shall be provided at all dead ends or at any other place as
required by Engineer-In-Charge, In such cases these shall as far as possible, be set
parallel to each other.
                                          TS 74
              The stay rod where so specified in the contract shall be protected with
G.I. pipe which shall not be less than 5 cm. diameter and 1.5 meter, long placed so as
to be 0.6 meter below ground. The length of stay rod shall accordingly be increased.


              If the stay rod can not be erected in accordance with the above clauses
due to roadways or obstructions, building etc. bow slay, fly stay or Strut which ever is
suitable to the location shall be used.
              (a)     Bow Slay: Bow stay shall consist of a brace with in pulley on the
outer end to allow for free motion of stay wire in addition to other accessories
required for the set as mentioned in the stay wire shall be clamped with the top of
pole of the other end to a stay rod passing over the pulley of brace. The brace shall be
clamped at 2/3rd height of the pole from the ground level. The stay rod shall be
embedded in cement concrete foundation in the usual manner as near as possible to
the pole.
              (b)   Fly stay: The fly stay shall consist of a fly pole wire running over
the obstruction and usual stay alignment for the fly pole.
              The stay wire crossing the obstruction shall be clamped at the one end to
the top of the pole carrying conductors and on the other end to the top of the fly pole
with a turn buckle. The fly stay shall be provided with a stay in the usual manner. The
fly stay shall be taken at such a height as may be directed by the Engineer-in-Charge.
When the fly stay is taken across a road it shall conform to traffic regulations.
              (c)     Strut : The strut shall be buried in the ground as mentioned in
and erected in the same manner as the support. It shall rest on the pole squarely and
shall be firmly secured.
              Erection of line material :
              Cross-arms:     Cross-arms shall be clamped lo the support properly
taking into consideration the orientation of the lines.
              "D" Iron Clamps:
              (a)    "D" iron clamps shall be used where vertical configuration of
                     conductors is adopted
                                          TS 75
              (b)     "D" iron clamps shall be fixed to the support either by a through
                      bolt and nut arrangement or by suitable pole clamp with bolt and
                      nut.
              (c)     These shall be installed vertically on the support complying with
                      the vertical clearance required between the conductors indicated
                      in.
              Erection of insulators:-
              Pin insulators / shackle insulators / disc insulators shall be created on
the cross arms and "D" iron clamp as specified in the contract or as directed by the
Engineer-in-Charge.
              Shackle insulators shall be used in conjunction with "D" iron clamp
when the configuration of conductors is vertical. These shall also be erected on cross,
arms at intermediate support in case of long lines; deviation from straight line more
than 30° terminal position, junction poles etc.
              Care shall be taken that insulators are not damaged during erection and
damaged insulators are not used.
42     Stringing of conductors:

       Handling:-
       (a)    The general precautions during storage and handling shall be taken.
       (b)    More attention is necessary during handling aluminum conductors
              because of their relative softness.
       (c)    While paying off, the conductors shall be taken from the top of the drum
              and drum rotated in the direction of the arrow on it.
       (d)    Care shall be taken during paying off to avoid contact with steel works,
              fence, etc. by giving soft wood protection using wooden rollers etc.
              Proper tools shall be used for stringing work.

              During stringing operation, standard sag tables or charts shall be
              followed.

              Care shall be taken to see that there are no kinks in the conductors.

              Joints in conductors shall be staggered. Mid span joints in conductors
              shall be generally avoided.
                                          TS 76


              After stringing the conductors it shall be clamped permanently with
shackle or strain clamps. Angle or section points shall be selected while pulling up
conductors. All strands of the conductors must be gripped securely when pulling the
conductors.
              When tile work is carried out adjacent to and for connecting to an
existing system in operation or long parallelism to an existing        line is involved
adequate safety precautions for isolation, discharging, earthing etc. shall be taken to
ensure that the lines do not inadvertently get charged from live supply. Where "Permit
to work" system is in vogue, regular safety procedure prescribed should be complied
with.
43.     Jumpers :
              While stringing conductors of sufficient length be kept at shackle
termination or making jumpers.
              Jumpers shall be neat and as far as possible symmetrical to the run of
conductors. These shall be so made to prevent occurrence of fault due to wind or bird.
              When necessary jumpers shall be insulated conductors or insulated as
directed by Engineer-in-Charge.
               Parallel-groove(PG) clamp may be preferred to binding of conductors
at jumper location or service taps.
              Jumpers used shall normally be of the same material as the line
conductor and be of adequate current carrying capacity. If the material of the jumper
wire is different from that of the conductor, suitable bimetallic clamps should be used.
if copper to aluminum bimetallic clamps are to be used, it should be ensured that the
aluminum conductor is situated above the copper conductor so that no copper
contaminated water comes in contact with aluminum.
               For high voltage lines the jumper should be so arranged that there is a
minimum clearance of 30 cm. under maximum deflection condition due to wind
between the live jumper and other metallic parts. Tills may involve erection of pin
insulators specially for fixing the jumpers.
                                          TS 77
44.     Binding of conductors:
               To binding of the conductor to the insulator shall be sufficiently firm
and tight to ensure that no intermittent contacts develop.


               The ends of binding wire shall be tightly twisted in a closely spaced
spiral around the conductor to ensure good electrical contact and to strengthen the
conductor.

45.     Erection of guard :
               At all road crossing of overhead lines, crossing with other line and
between HV and LV/MV line carried on the same support, guard shall be provided.
               The guard wires shall be bonded to earth.
               The guard wire shall run so as to have minimum clearance as indicated
in clause 39(b).
               Cage guard wire shall be provided for distribution lines of vertical
configuration.
               Cradle guard shall be used for distribution lines of horizontal
configuration.
               In case of cradle / cage guards, at least 9 laces shall be provided for each
span.

46.     Cutting of trees etc.
               Construction of over head line may include cutting branches of trees or
clearing of other obstructions that may come in the way of over head lines but this
must be done with the approval of Engineer-in-Charge.

47.     Earthing :
               Earthing installation shall conform to various clauses under para 26.
               All metal supports and all reinforced and pre stressed cement concrete
supports of overhead lines and metallic fittings attached there to shall be permanently
and efficiently earthed. In the case of wood/RCC/PCC poles, all insulator pins. cross
arms, stays street light brackets and other metallic fittings shall be bonded to be earth
lead.
                                           TS 78


                Junctions end terminal locations and all special structures may be
selected for connecting to earth.

                The lead from earth electrode shall be suitably protected by a 15 mm.
dia G.I. pipe up to a height of 3 m. from the ground level.

                The protection pipe and the earth lead shall be suitably clamped to the
support.

48.    Safety and protective device :-

                Danger Board - All supports carrying HV lines shall be fitted with
danger plates conforming to I.S. 2551-1963           at height of 3m from the ground
indicating the voltage of the line.
                Anti   climbing     device:-   Necessary   arrangement   for preventing
unauthorized persons from ascending any of the supports carrying HV lines, without
the aid of a ladder or special appliances, shall be made as directed by the Engineer-In-
Charge. Unless where otherwise specified, barbed wire conforming to IS 2784-1969
having four point barbs spaced 75 ± 12mm. apart and weighing 108/125 gm. /m. shall
be wrapped helically with a pitch of 75 cm. around the limb of the support and tied
firmly commencing from a height of 3.5 m. and up to a height 5 or 6 m. as directed by
Engineer-In-Charge.

49.        Lightning arresters :

       (a)     Horn gap type lighting arrestors for LV/MV and surge diverter suitable
                for MV lines shall be employed with each phase at terminal and other
                places where specified depending upon local climatic condition and
                mounted on poles or a cross-arms as directed by Engineer-In-Charge.
       (b)      In the case of Horn gap type arrester, a short and definite air gap must
                be maintained between the horns. Tins gap shall not exceed 2 cm.
                                           TS 79
       (c)    Pellet or Thyrite type lighting arrester suitable For H.T lines shall be
              installed one unit per phase at the terminations, transformers, stations,
              etc. as directed by Engineer-In-Charge.
       (d)    These devices shall be conducted ahead of fuse if any, provided
       (e)   Independent earth electrode shall be provided for lightning arresters.
       (f)    The earth lead from the earth electrode to the lighting arrestor shall be
              continuous and if desired insulated throughout above earth surface by
              alkathene pipe.
50.    Service entry and service fuses :
              No service connection shall be taken on an over head line except at a
point of support.
              The service line shall be guarded wherever required in accordance
with I.E. Rules 1956.
              Service connection shall be either through an overhead service or
underground cable as specified. In case of overhead service the same should be
provided either with:-
              (a)    Bare conductor or
              (b)    Insulated conductor

              Service connection with bare conductor : Any of the following
methods shall be adopted as specified:
              (a)    The bare conductors shall be strung with shackle insulators fixed
                     to cross-arms on both ends. The feeding end cross-arm shall be
                     fixed to the support and the one of the receiving end shall be
                     mounted on G.I. pipe of minimum dia 5cm. The bare conductors
                     shall be kept at a height of atleast 2.5m. or the top of the structure
                     in accordance with Rule 79 of I.E. Rules.        The G.I. pipe shall
                     be provided with double bends at the top. The pipe shall be
                     secured by atleast 2 clamps made of 50mm x 6mm.            M.S. flats
                     fixed firmly to the wall in the vertical position. It shall        in
                     addition be provided with a G.I. stay wire of 7/3.15 mm.
                     size anchored to the building with one eye bolt. Service
                                         TS 80
                     connection given with weather proof / PVC insulated bushes
                     shall be provided at both ends of this G.I. pipe.
              (b)    The bare conductors shall be strung with shackle insulators as
                     above except at the receiving end where the insulator shall be
                     fixed to a square or a rectangular wall bracket made of angle iron
                     of size not less than 50mm x 50mm x 6mm. The ends of the
                     bracket shall bend and split and embedded in the wall with
                     cement mortar. The bare conductor shall be kept atleast 1.2m.
                     away from the edge of the structure, in accordance with Rule 79
                     I.E. Rules. The service connection shall be given with weather
                     proof/ PVC insulated cable to G.I. pipe of minimum dia. 4 cm.
                     fixed to the wall. The G.I. pipe shall be bend downward near the
                     service entry. Well fitted wooden / PV.C bushes shall be
                     provided at the both ends of the G.I. pipes.
                     Service connection with      insulated    conductors :     Service
connection may be given by weather proof/ PVC insulated cables on G.I.. bearer wire.
the bearer wire should be stranded 7/20 G.I. or near above size. The bearer wires and
weather proof cables should be bunched together by porcelain reel insulators or
alkathene clips at intervals of 10 cm. One end of the G.I. bearer wire shall be attached
to a clamp which is fastened to the nearest pole carrying distribution lines from where
the service connection is intended to be given. The other end of the G.I. bearer wire
shall be fastened to 5 cm. dia. G.I. pipe (far a span up to 4.5m.) which is fixed to
the wall with guy etc. The G.I. pipe shall be fixed to an angle iron of size 38mm x
38mm x 6.4mm with suitable guy for high support and for span exceeding 4.5m.
Alternatively, when the height of the structure permits minimum ground clearance the
other end of this G.I. bearer wire may be fixed to a hook eye-bolt or bracket
embedded with cement mortar in the wall. The weather proof/ PVC insulated, cable
shall pass through G.I. pipe of minimum dia. 5 m. which is bent downwards. Wall
fitting wooden/PVC bushes shall be provided at both ends of the G.I. pipe. The bearer
wire should not be used as earth lead. The bearer wire should be earthed at both pole
ends and at the building end to the building earth.
                                          TS 81
              Service connection by winder ground cable : The service cable from
an overhead distribution line shall be fixed to the support with 2 Nos. of clamp of M.S
flat of size 50 mm. x 6 mm. This shall be protected up to a height of 3 m. from the
ground level by a G.I. pipe of adequate strength clamped to the support of 2 Nos. of
M.S. flat of size 50 mm. x 6 mm. The cable shall be laid through pipe while crossing
the roads, payments, masonry etc. The cable work shall be done in accordance with.
The service cable shall be terminated to an outdoor cable termination box fixed to the
support. The connection shall be given either by the core of the service cable directly
or through separate insulated leads.
              Service fuse : Service fuses carriers shall be of approved make and of
ample size to permit entry of ends of service lines connected to them. They shall be
fixed at the distribution line support from which the service line is tapped.
51.     Numbering Supports:
              All supports shall be numbered as directed by the Engineer-in-Charge.
              Separate number plates may be used if so specified.
52      Painting and repainting of supports, cross-arms etc. :
              Treatment of all supports and line materials before or at the time of
erection shall be done in accordance with the relevant sub para of 29.
              After erection the external surface of main support above ground level
and all pipe fittings shall be painted as directed by the Engineer-in-Charge.
              The following procedure for painting / repainting shall be adopted.
              Preparation of the surface : All rust and scales shall be removed by
scrapping or by brushing with steel wire brushes. All dust and dirt shall be carefully
and thoroughly wiped away. Painting shall not be done when the surface is wet.
              Primer coat shall be applied with red oxide paint.
              When the primer coat has dried up and before any moisture, dirt, dust
etc. settle down on the surface, the paint of desired shade shall be applied. Application
shall be done with brushes and the paint shall be spread as evenly and smooth as
possible. The surface shall be given two or more coats as directed and shall finally
present a uniform appearance and glassy texture.
                                           TS 82
53.    Testing of Overhead Line :
                Before connecting the services to the transformer equipment etc., a
pressure test of appropriate standard shall be carried out on line as directed by
Engineer-in-Charge. Before charging the M.V. lines, the same shall be tested with a
500 V. megger for insulation.
                Where pressure test is not done on H.V. lines it shall be tested with a
2500 V / 5000 V megger for insulation before charging.

54.     Commissioning:

                The distribution lines shall be charged only if the pressure megger test is

satisfactory.

                The lines shall be commissioned in the presence of Engineer-in-Charge.
                For all works costing more than Rs. 10000 completion certified after
completion of work as given in the Appendix-E shall be submitted to the Engineer-in-
charge. Completion plan drawn to a suitable scale in tracing cloth with ink indicating
the following along with three blue print copies of the same shall also be submitted.
                (a)    Central layout of overhead lines.
                (b)    Location of each support, stay length of each span, number of
                       spans provided with cradle guard, guard earth, number and size
                       of each line conductor, joints in conductors size of earth
                       continuity wire, lightning protective devices, service brackets /
                       entry, fuses etc.
                (c)    For the cable work done, if any, layout of power cable, size and
                       number of cores, type and length.
                (d)    Details of voltage and system of supply, height of support,
                       configuration, spacing of conductors, average sag, total route
                       length, scale of drawing etc. in a tabular form.
                (e)    Name of work, job number, accepted tender references, date of
                       completion,    names    of   division   /sub-division,   names   of
                       contractors with their signatures.
                                          TS 83


              In the case of works costing less than Rs. 10,000.00: Completion plan
shall be prepared by the department and signed by the contractor before final payment
is made.
              Whenever additions and alterations into existing installations are carried
out, the plans showing the layout of distribution system shall be modified and brought
up to date.
55.    CABLE WORK:

              This specification covers the requirement for the selection and
installation of Power cables for low, medium and high voltage applications.

              Types of Cables :

              The cables for low and medium supply shall be PVC insulated and PVC
sheathed conforming to I.S. 1554 part-I 1964.
              The cables for applications above 1.1 KV but up to and including
11 KV supply shall be either PVC insulated and PVC sheathed conforming to IS
……. part-II 1970 or paper insulated sheathed conforming to IS 693-1973.
              The cables shall have solid /stranded aluminium conductors.
              Where paper insulated cables arc used, in predominantly vertical
situation, these shall be of non-drawing type.

              Armouring and Servicing :

              Short runs of cables laid in pipe, closed masonry trenches and similar
protected / secured enclosures need not be armoured PVC cables.. When armoured,
shall have galvanized steel wire (flat or round) for armouring. Paper insulated cables
shall have for armouring, double laver of steel tape for normal applications. Steel wire
armouring, is preferred, where the cable is liable for tensile stresses in applications
such as vertical runs suspended on brackets or land in fail i.e. likely to subside.
              Serving over armouring in paper insulated cables shall consist of a
complete layer or layers of suitable compounded Hessian materials.
                                          TS 84
                Section Of Cables:
                Cable sizes shall be selected considering the current carrying capacity,
voltage drop, maximum short circuit, duty and the period of short circuit meet the
present and future anticipated loads.
                Guidance for the selection of cables shall be derived from the relevant
Indian Standards such as I.S. 3961(Part-l) 1967.
                While deciding cable sizes, derating factor for type and depth of laying
grouping, ambient, temperature, ground temperature and soil resistivity shall be taken
into account.
                Storage And Handling:
                Cable drums shall be stored on a well drained, hard Surface,
preferably of concrete so that the drums do not sink in the ground causing rot and
damage to the cable drums.
                During storage periodical rolling of drums once in three months through
90 degree shall be done especially in the case of paper insulated cables, rolling shall
be done in the direction of the arrow marked on the drum.
                It should be ensured that both ends of the cables arc properly sealed to
prevent ingress / absorption of moisture by the insulation.
                Protection from rain and sun is preferable. Sufficient ventilation
between cable drums should be ensured during storage.
                The drums shall always be rested on the flanged end not on the flat
sides.
                Damaged battens of drums should be replaced if necessary.
                When cable drums have to be moved over short distance that should be
rolled in the direction of the arrows marked on the drums.
                For transportation over long distances, the drum should be mounted on
the cable drum wheels strong enough to carry the weight of the drum and pulled by
means of ropes. Alternatively, they may be mounted on a trailer or on a suitable
mechanical transport.
                While unloading cable drums from vehicles, a crane shall preferably be
used. Otherwise the drum shall be rolled down carefully on a suitable ramp or rails,
where necessary.
                                          TS 85
              While removing cables the drums shall be properly mounted on jacks or
on a cable wheel or any other suitable means making sure the spindle jack etc. is
strong enough to take the weight of the drum.
              While transferring cable from one drum lo another the barrel of the new
drum shall have a diameter not less than that of the original drum.
              The cable shall not be bent sharp to a small radius. The minimum safe
bending radius for all types of PVC cables shall be taken as 12 times the over all
diameter of the cable. The minimum safe bending radius for paper insulated cables
shall be as follows. Wherever practicable, large radius should be adopted. At joints
and terminations, the bending radius of individual cores of a multi core cable shall not
be less than 15 times it's over all diameters.




                                       TABLE -1
Minimum Bending Radius-Paper Insulated Cables
                                           Minimum Bending Radius
  System Voltage                                          Multi core
                           Single Core
                                                Unarmoured           Armoured
Up to & including
                               20 D                   15 D                 12 D
     11 KV


              Where "D" is the over all diameter of the cable.

              Cables with kinks and straightening kinks or with similar apparent
defects like defective armouring, etc. shall not be installed.

56.    Installation:

              General:      The cable installation including necessary joints shall be
carried out in accordance with the specifications given herein. For details not covered
in these, specifications I.S. 1255-1967 shall be followed.
              Route:
              Before the cable laying work is under taken the route of the cable shall
be decided by the Engineer-in-charge.
                                          TS 86
              While shortest practicable route should be preferred cable runs shall
generally follow fixed developments such as roads, foot-paths etc. with proper offsets
so that the future maintenance identification etc. are rendered easy. Cross country runs
to shorten the route length is not desirable as it would be set with route identification
and maintenance problems besides posing difficulties during later developments
of open areas etc.
              While selecting cable routes corrosive soils, ground surrounding sewage
effluent etc. shall be avoided, where this is not feasible, special precaution as decided
by the Engineer-In-Charge, particularly for HV cable installation shall be taken.
              As for as possible, the alignment of the cable route should be decided
taking in to consideration the present and future requirement of other agencies and
utility services affected by it the existence of any cable in the vicinity as may be
indicated by cable markers or cable schedule or drawings maintained for that area,
possibilities of widening of roads / lanes, storm water drains etc. Cable route shall be
planed away from the drains and near the property, especially in the case of MV/LV
cables subject to any special local requirements that may have to be necessarily
complied with.

              Whenever cables are laid along well demarcated or established roads,
the LV/MV cables shall be laid further from the kerb line than HV cables.

              Cables of different voltages and also power and control cable should be
kept in different trenches with adequate separation. Where available space is
restricted, LV/MV cables shall be laid above HV cables.

              Where cables cross one another, the cable of the higher voltage shall be
laid at a lower level than the cable of lower voltage.

              Proximity to communication cable :

              Power and communication cables shall as far as possible cross at right
angles. Where power cables are laid in proximity to communication cables the
horizontal and vertical clearances shall not normally be less than 60 cms.
                                           TS 87


57.    Laying methods:

               Cables shall be laid direct in ground in pipes, closed ducts, in open
ducts or on surface depending on environmental conditions.
               During the preliminary stages of laying the cable consideration should
be given to proper location of the join position so that when the cable is actually laid
the joints are made in the most suitable places. As far as possible water lagged
locations, carriage ways, pavements, proximity places, ducts, pipes, racks, etc. shall
be avoided for joint position.

               Laying direct in ground :

               General:    This method shall be adopted where no frequent excavations
are encountered the cable route is through open country, along roads/lanes and where
re excavation is easily possible without affecting other services.

58.    Trenching :

       (a)     Width of trench: The width of trench shall First determined on the
               following basis :-
       (i)     The minimum width of trench for laying single cable shall be 35 cm.
       (ii)    Where more than one cable is to be laid in the same trench in horizontal
               formation, the width of trench shall be increased such that the inter-axial
               spacing between the cables, except where otherwise specified shall be at
               least 50 cm.
       (iii)   There shall be a clearance of at least 15 cm. between axis of the end
               cables and the sides of the trench.
       (b)     Depth of trench:     The depth of trench shall be determined on the
               following basis.
       (i)     Where tables are laid in single tier formation the total depth of trench
               shall not be less than 46 cm. for cables up to 11 KV and 1.0m. for cables
               above 11 KV.
                                   TS 88
(ii)    When more than one tier of cables is unavoidable and vertical formation
        of laying is adopted, depth of trench in b(ii) above shall be increased by
        30 cm. for each additional tier to be formed.
(c)     Excavation of trenches:
(i)     The trenches shall be excavated in reasonably straight lines. Wherever
        there is a change in direction, suitable curvature shall be provided.
(ii)    Where gradients and changes in depth are unavoidable those shall be
        gradual.
(iii)   Excavation should be done by any suitable means-manual or
        mechanical. The excavated soil shall be stacked firmly by the side of the
        trench such that it may not fallback into the trench.
(iv)    Adequate precautions should be taken not lo damage any existing
        cable(s) pipes or other such installation in the proposed route during
        excavation. Wherever brick tiles or prospective covers of bare cables are
        encountered, further excavation shall not be carried out without the
        approval of the Engineer-in-Charge.

(v)     Existing property exposed during trending shall be temporarily
        supported or Dropped adequately by the Engineer-In-Charge. The
        trenching in such cases shall be done in short length, necessary pipes
        laid for passing cable therein and the trench refilled in accordance.
(vi)    If there any danger of a trench collapsing or endangering adjacent
        structures the sides should be well shored up with timbering and/or
        sheeting as the excavation proceeds. Where necessary these may even
        be left in places when back filling the trench.
(vii)   Excavation through lawns shall be done in consultation with the staff of
        the department/owner concerned.
(viii) The bottom of the trench shall be in level and free from stone back bats
        etc. The trench shall then be provided with a layer of clean dry sand
        cushion of not less then 8cm. in depth.
                                    TS 89
       Laying of cable in trench:

(a)    At the time of issue of cable for laying the cores shall be tested For
       continuity and insulation resistance.
(b)    The cable drum shall be properly mounted on jacks or on a cable wheel
       at a suitable location making sure that the spindle jack etc. are strong
       enough to carry the weight of the drum without failure and that the
       spindle is horizontal in the bearings so as to prevent the drum creeping
       to one side wile rotating.
(c)    The cable shall be pulled over rollers in the trench steadily and
       uniformly without jerks and strains. The entire cable length shall as far
       as possible be laid off in one stretch. However where this is not possible
       the remainder of the cable may be removed by 'Flaking' i.e. by making
       one long loop in the reverse direction.
(d)    (i)     After the cable has been uncoiled and laid in the trench over the
       rollers the cable shall be lifted slightly over the rollers beginning from
       one end by helpers standing about 10 m. apart and drawn straight. The
       cable should then be taken off the rollers by additional helpers lifting
       the cable and then laid in a reasonable straight line.
(ii)   For short runs and sizes up to 50 Sq. meter of cables up to 11 KV grade
       any oilier suitable method of direct handling and laying can be adopted
       with the prior approval of the Engineer-in-Charge.
(e)    When the cable has been properly straightened the cores are tested for
       continuity and insulation resistance the cable is then measured. The ends
       of all lead sheathed cables shall be sealed with solder immediately.
       Incase of PVC cables suitable moisture tape shall be used for this
       purpose.
(f)    (i)    Cable laid in trench in a single tier formation shall have a
       covering of clean dry sand of not loss than 17 cm above the basic
       cushion of sand before the protective cover is laid.
(ii)   In the case of vertical multi-tier formation after the first cable has been
       laid a sand cushion of 30 cm shall be provided over the initial bed
       before the second tier is laid. If additional tiers are formed each of the
                                         TS 90
              subsequent tiers also shall have a sand cushion of 30 cms. as stated
              above. The top most cable shall have a final sand covering not less than
              17 cms. before the protective cover is laid.
       (g)    At the time of original installation approximately 3m. of surplus cable
              shall be left on each end of the cable and on each side of underground
              joints (straight through/Tee/Termination) and at entries and places as
              may be decided by the Engineer-in-Charge. The surplus cables shall be
              left in the form of a loop. Where there are long runs of cable lengths,
              loose cable may be left at suitable intervals as specified by the
              Engineer-in-Charge.
       (h)    A Final protection to cables shall be laid as described below to provide
              warning to future excavators of the presence of the cable and also lo
              protect the cable against accidental mechanical damage by pick-axe
              blows, etc.
              The cables shall be protected by second class bricks of not less than 20
cm. by 10 cm. (nominal size) (bricks to be laid breadth wise) or protection covers of
RCC slabs placed on top of the sand for full length of the cable to the satisfaction of
the Engineer-in-charge. Where more than one cable is to be laid in the same trench
this protective covering shall cover all the cables and project at least 5 cm. over the
sides of the end cables.
59.    Back Filling
       (a)    The trenches shall be then back-filled with excavated earth free form
              stone or other sharp edged debris and shall be rammed and watered if
              necessary in successive layers not exceeding 30 cm. Unless otherwise
              specified a crown of earth not less than 5 cm. in the centre and tapering
              towards the sides of the trench shall be left allow for subsidence. The
              crown of earth however should not exceed 10 cm. so as not to be a
              hazard to vehicular traffic. The temporary re-instatements of roadways
              should be inspected at regular intervals particularly during the wet
              weather and any settlement should be made good by further filling as
              may be required. After the subsidence has ceased trenched not through
              roadways or other paved areas shall be restored to the same density and
              material as the surrounding area and repaved to the satisfaction of the
              Engineer-in-charge.
                                           TS 91
         (b)     Where road beams or lawns have been cut or kerb stones displaced the
                 same shall be repaired and made good except turfing / asphalting to the
                 satisfaction of the Engineer-in-charge and all surplus earth or rock
                 removed to places as specified.
Route Makers :
         (a)     Route makers shall be provided along straight runs of the cables at
                 locations approved by the Engineer-in-charge and generally at intervals
                 not exceeding 100m. Markers shall also be provided to identify change
                 in the direction of the cable route and also for location of every
                 underground joint.
         (b)     Route makers shall be made out of 100mm x 100mm x 5mm G.I.
                 Aluminum plate welded or bolter on to 35mm x 35mm x 6mm angle
                 iron 60cm. long. Such plate makers shall be mounted parallel to and
                 0.5m or so away from the edge of the trench.
                 Alternatively cement concrete 1 : 2 : 4 ( 1 cement : 2 coarse sand : 4
graded stone aggregate of 20 mm nominal size) 60 cm x 60 cm x 10 cm in size shall
be laid flat and centered over the cable. The concrete markers unless otherwise
instructed by the Engineer-in-charge shall project over the surrounding surface so as
to make the cable route easily identifiable.
         (c)     The word 'cable' and other details such as voltage grading size etc. as
                 furnished by the Engineer-in-charge shall be inscribed or the marker.
Laying in pipes / closed ducts :
                 In location such as road crossing entry to building on poles in paved
areas etc. cables shall be laid in pipes or closed ducts.
                 Stone ware pipes, G.I., or spun reinforced concrete pipes shall be
used for such purposes. In the case of new construction pipes as required shall be laid
along with the Civil works and jointed according to the instructions of the Engineer-
In-Charge. The size of the pipe shall be decided by the Engineer-in-Charge and shall
not be less than 10 cm. in diameter for single cable and not less than 15 cm for more
than one cable. These pipes shall be laid directly in ground without any special bed
except for stone ware pipe which shall be laid over 10 cm. thick cement aggregate
1:5:10         (l cement: 5 coarse sand: 10 graded stones aggregate of 40 mm. normal
size) bed. No. sand cushioning or tiles need be used in such situations. Unless
                                           TS 92
otherwise specified, the top surface of pipes shall be at a minimum depth of 1 m. from
the ground level when laid under roads, pavements etc.
                The pipes or road crossing shall preferably be on the skew to reduce the
angle of bend as the cable enters and levels the crossing. This is particularly important
for high voltage cables.
                Manholes of adequate size as decided by the Engineer-in-Charge shall
be provided to facilitate feeding/drawing in of cables and to provide working space
for persons. They shall be covered by suitable manhole covers with frame of proper
design.
                Pipes shall be continuous and clear of debris or concrete before 'cable is
drawn. Sharp edges at ends shall be smoothened to prevent injury to cable insulation
or sheathing.
                Pipes for cable entries to the building shall slope downwards from the
building and suitably sealed to prevent entry of water inside the building. further the
length of pipes at the building shall be suitably sealed lo avoid entry of water.
                All chases and passages necessary for the laying of service cable
connection to building shall be cut as required and made good to the original finish
and to the satisfaction of the Engineer-in-Charge.
                Cable grips / draw wires and inches etc. may be employed for drawing
cables through pipes / closed ducts etc.
                Laying in open ducts:
                Open ducts will suitable removable covers shall be preferred in sub-
stations switch rooms, plant rooms, work-shop etc.
                The cable ducts should be of suitable dimensions so that the cable can
be conveniently laid. If necessary cables may be fixed with clamps on the walls of the
duct or taken in troughs in duct. The duct should be covered with removable slabs or
chequerred plates.
                Ducts may be filled with dry sand after the cable is laid and covered as
above or finished with cement plaster especially in high voltage applications.
                Slices or Joints of any type shall not be permitted inside the ducts.
                As for as possible laying of cables with different voltage ratings in the
same duct shall be avoided.
                                          TS 93
              Where considered necessary, hooks or racks shall be provided for
supporting the cables in masonry / concrete cable ducts, cable troughs. Otherwise
cable shall be laid direct in the trench or trough etc. While deciding the lay out of
cables in such ducts care should be exercised to ensure that unnecessary crossing of
cable is avoided.
              Laying on surface:
              Tills method may be adopted in places like switching stations, factories,
tunnels, rising mains in buildings through Special packages etc. The materials used
shall be as approved by Engineer-in-Charge.
              The cables may be laid in troughs or brackets at regular intervals or
directly cleated to wall / ceiling. When laid over bracket supports, the cables shall be
clamped to prevent undue sag.
              Cable clamps shall be made from materials such as mild steel, porcelain,
wood, aluminum, etc. In case of single core cables the clamps shall be of non-
magnetic material. A suitable non-corrosive packing shall be used for clamping
unarmoured cables to prevent damage to the cable sheaths.
              Cable identification tags: Wherever more than one cable is laid/run
side by side marker lags as approved inscribed with cable, identification details shall
be permanently attached to all the cables in the main holes / pull pits /Joint pits
entry points in buildings / open-ducts, etc. These shall also be attached to various
cables laid direct in ground at suitable intervals as decided by the Engineer-in-Charge
before the trenches are filled up.
60.        Jointing:
              Jointing work shall be earned out only by a licensed / experienced cable
jointer.
              At the preliminary stages of laying a cable at proper jointing position
should be selected.
              Sufficient surplus cable shall be left on each side of joints.
              Joints shall be staggered by 2 to 3 meter when two or more cables are
laid together in the same trench.
              A caution board indicating "Caution - cable jointing works in progress"
shall be displayed to warn the public and traffic where necessary.
                                         TS 94
              Jointing pits shall be of sufficient dimensions as to allow easy and
comfortable working. The sides of the pit shall be well protected from loose earth
failing in to it shall also be covered by a tarpaulin to prevent dust and other foreign
matter being blown on the closed joint and jointing materials.
              Sufficient ventilation shall be provided during jointing operation in
order lo disperse fumes given out by fluxing.
              Jointing materials and accessories like conductor ferrules solder, flux,
installing and protective taps filling compound jointing boxes, etc., of right quality
and correct sizes conforming to relevant Indian Standards wherever they exist shall be
used. The design of the joint box and the compositions of the filling compound shall
be such as to provide as effective sealing against entry of moisture in addition to
affording proper electrical characteristic to joints. Where special type of connector its
or epoxy resin spliced joints are specified materials approved for such application
shall be used and instructions of the manufacturer / supplier of such material shall be
strictly followed.
              Insulation resistance of cables to be jointed shall be measured with 500
V. megger up to 11 KV grade and with 2500 / 5000 V. megger for cables of higher
voltages. Unless the insulation resistance values are satisfactory jointing shall not be
done.
              Before jointing is commenced all safety precautions like isolation
discharging earthing, etc. shall be taken to ensure that the cable would not be
inadvertently charged from live supply. Metallic armour and external metallic ending
shall be connected to earth. Where "permit to work" system is in vogue safely
procedures prescribed in I.S. 5216-1969 shall he complied with-vide Appendix-1)
              Cores of the cables must be properly identified before jointing.
              Whenever aluminium conductor is exposed to outside atmosphere a
highly tenacious oxide film is formed which makes the soldering of aluminium
conductor difficult. The oxide film should be removed using appropriate type of flux.
              The clamps for the armour shall be cleaned and tight.
              Where a cable is to be jointed with the existing cable the sequence
should be so arranged as to avoid crossing of cores while jointing.
                                         TS 95
61.    Jointing procedure:
              While it would be best to follow strictly the instructions for jointing
furnished by the manufacturers/ suppliers of cable and joint boxes a brief on the
jointing procedures for paper insulated and PVC cables is given for general guidance
in Appendix H.
              All indoor and outdoor jointing of paper insulated cable shall be done
accordance with the provision of section 11 of I.S.1255-1967.
              All outdoor jointing of PVC cable shall be done using best quality or
compound and joining materials. For indoor termination of PVC cables joints will
compression type glands shall be preferred.
62.    Testing;
              All cables before laying shall be tested with a 500 V. megger for 11 KV
grade or with 2500/5000 V. megger for cables of higher voltages. The cable cores
shall be tested for continuity or absence of cross phasing, insulation resistance to
earth/sheaths/armour and insulation resistance between conductors.
              All cables shall be subjected to above mentioned tests during laying
before covering the cables by protective covers and back filling and also before the
jointing operations.
              After laying and jointing, the cable shall be tested for one minute with
1000 V. megger for cables of 11 KV grade, and with 2500 / 5000 V. megger for
cables of higher voltages.

63     Completion Plan And Completion Certificate :

34.6.9.1     The work shall be carried out in accordance with the drawings enclosed
with the tender and also in accordance with the modifications thereto from time to
time approved by the Engineer-in-Charge.

              For all works costing more than Rs. 10,000 completion certificate after
completion of work as given in Appendix C shall be submitted to the Engineer-in-
charge. Completion plan drawn to a suitable scale in tracing cloth with ink indicating
the following along with three blue print copies of the same shall also be submitted.
                                        TS 96
General:-
             (a)    Layout of cable work.
             (b)    Length, size, type and grade of cables.
             (c)    Methods of laying, i.e. direct in ground, in pipes, etc.
             (d)    Location of each joint with jointing method followed.
             (e)    Route marker and joint marker with respect to permanent land
                    marks available at site.
             (f)    Name of work, job number, accepted lender reference, dale of
                    completion, names of division and sub division, names of
                    contractor with their signature and scale of drawing.
             In the case of work costing less than Rs. 10,000, the completion plan
Shall be prepared by the department and signed by contractor before final payment is
made.
             Wherever the previously laid cable is cut and additional joints etc. are
introduced, the cable records shall suitably be amended.
64.          PVC SPACER:


             PVC spacer with PVC Nut & Bolts shall be used at every 10 meters for
             3 phase 5 wire L.T. Lines for phase to phase separation.
65.          NUT-BOLTS AND WASHERS:

             All Nut Bolts and washers used shall be hot dip galvanized.


66.          L.T. DISTRIBUTION BOARD:

             L.T. Distribution board shall be fabricated from 2 mm. thick M.S. sheet
             duly degreased, derusted, phosphalised and painted with one coat of
             zinc chromate primer and two coats of epoxy paint (grey outside and
             white inside). The distribution board shall be suitable for outdoor
             installation.
                                         TS 97


        TECHNICAL SPECIFICATION FOR 33 KV H.T. LINE


              Triangular Configuration: - Minimum Distance between Centers of
                                          Pin holes ------- 1525mm.


              The conductors are erected in such a way that they form an equilateral
pattern as per T.S.99 -T.S. 100- T.S.101, T.S. 102.   The minimum clearance between
conductor and ground, between conductor and other service lines of different voltages
shall be in accordance with rule 77, 79, 80 and 81 of Indian Electricity Rules.


              The Bridling V-Cross arms for road crossing and 20mm dia stay set
shall be provided as per drawings TS-103, TS-104, TS-105 respectively. Each pole
and cross arms shall be earthed as per standard already described.
TS 98
TS 99
TS 100
TS 101
TS 102
TS 103
TS 104
TS 105
TS 106
                                        TS 107


                        MAKES OF MAJOR EQUIPMENTS


1.     Transformer         :
       (i) 33/11 KV        :      BHEL/KIRLOSKAR/CROMPTON/VOLTAMP/
                                  INDOCOIL/GEC/GEF/TESLA/ALSTROM/STAR
                                  DELTA/KOSHA ELECTRICALS

       (ii) 11/0.4 KV      :      M.P. TRANSFORMER/TESLA/STAR DELTA/
                                  BHEL/KIRLOSKAR/VOLTAMP/ALSTHOM/
                                  MAYUR/POWER/ELECTRO POWER/KOSHA
                                  ELECTRICALS

2.     V.C.B.              :      BHEL/SLEMENS/ABB/JYOTI/CROMTON/
                                  ALSTHOM/NGEF.

3.     C.T./P.T.           :      CROMPTON/JYOTI/AE/KAPPA
       For 33/11 KVA

4.     H.T. CAPACITOR :           ASHIAN/CROMPTON/L & T

5.     MCCB/MCB            :      L & T/JYOTI/GEC/ALSTHOM/SIEMENS

6.     A.B. SWITCHES/ :           ATLAS/SOUTHERN/PATCIL/NATIONAL
       ISOLATOR

7.     LIGHTING            :      ELPRO/IGE/CROMPTON/OBLUM
       ARRESTORS

8.     D.O. SET            :      ATLAS/SOUTHERN

9.     CABLES              :      GLOSTER/FINOLEX/HAVELLS/NICCO/UNI
                                  STAR/PLAZA


Note : (1)   The Engineer-in-charge shall approve equivalent make of specified
             standards, if required for the items listed above.
       (2)   For the item whose makes, have not been indicated the Engineer-in-
             charge shall have powers to fix the same, confirming to specified
             standards.
                                       TS 108


                 REFERENCE TO IS-CODES OF MAJOR ITEMS


1.    Transformer                                :   IS- 2026, 1962
2.    Transformer Accessories                    :   IS- 3639 - 1966
3.    Transformer Oil                            :   IS- 335, 1972
4.    Loading of Transformer                     :   IS- 6600 - 1972
5.    Transformer Bushing                        :   IS- 2099 - 1973, 3347
6.    Earthing                                   :   IS- 3043 - 1987
7.    Over Head Power Lines                      :   IS- 5613
8.    P.C.C. Poles                               :   IS- 1678 - 1960
9.    Stay Wire                                  :   IS- 2141 - 1968
10.   Insulators                                 :   IS- 1445, 731 - 1971
11.   ACSR Conductors                            :   IS- 398 - 1961
12.   Lightning Arrestors                        :   IS- 3070 - 1965
13.   Danger Board                               :   IS- 2551 - 1963
14.   Cables                                     :   IS- 1554
15.   Installation of Cables                     :   IS- 1255 - 1967
16.   Isolator Switch                            :   IS- 9921 - 1981
17.   Code of practice for design installation
      and maintenance of over head power
      lines                                      :   IS- 5613 - Part- I & II,
                                                     Section - I & II 1969/1970

				
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