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ELECTRICITY

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					            ELECTRICITY

Generating Methods:

   HYDRO (Water)

   SOLAR (Sun)

   WIND (Windmill)

   NUCLEAR (Chemical reaction)

   SOLID FUEL (Coal, turf)


In each of the above cases the energy is harnessed and
used to rotate turbines which generate the electrical
power (energy)


Generating Stations:

Hydro -        Ard na Crusha, Limerick
               Poolaphouaca, Wicklow

Solid Fuel -   Moneypoint, Clare

Nuclear -      Selafield, G.B.
Kilo Watt Hours: The amount of electrical energy
being used


Voltage:       Measure of electrical pressure and is
               defined in terms of energy required to
               move an electrical charge (unit V)

Current:       Measure of the rate of flow of electricity
               in a circuit (unit Ampere or Amp.)

Power:         Measure of the amount of work which can
               be done by electricity at a given currency
               and voltage (unit Watt)


            W=VI

V = Voltage
I = Current
W = Power


           V=IR
V = Voltage
I = Current
R =Resistance

Resistance: This is the resistance of a circuit to the flow
of current and where there is a large resistance the
voltage must be greater to ensure a constant current
MORE TERMS:


Conductor:   Material which permits the flow of
             electrons (eg Copper)


Insulator:   Material which resists the flow of
             electrons (eg P.V.C. or Bakelite)


Overload:    Where the current flowing in the circuit is
             greater than that permissible for the circuit


Bonding:     The linking together and earthing of metal
             piping near sinks, baths etc.


Earthing:    A safety feature which will short the
             circuit and hence blow / trip a fuse if a
             live wire becomes in contact with the
             metal casing of an appliance
            Domestic Electricity

Domestic supply to homes enters by way means of
meter box at rating of 220V. This meter box records the
amount of electrical units used


From the meter box the electricity enter the fuse box and
this is the distribution point for all the circuits ie sockets,
lights, cookers. If there is a problem the relevant circuit
breaker will trip and break the circuit


Each circuit is formed by 3 wires:

Live -          Red or Brown (positive)

Neutral -       Blue (negative)

Earth -         Green / yellow


Live acts as the server

Neutral as a return

Earth as a safety devise
               Safety

Safety is an extremely powerful source of energy in a
building and so should be installed with great care by
a professional


Fuse Box:     Electricity entering the house must pass
through a main fuse board which will trip off and
break the circuit if there is a power surge from
outside

Each circuit of the building has circuit breaker in the
fuse box which will trip in the case of an overload.
These are called m.c.b’s (miniature circuit breakers)

Plug tops should contain a fuse suitable for appliance
being used (the use of wire, silver foil etc.. is strictly
prohibited)

Circuits should be earthed and connected to a main
earth outside the house

Damp / wet appliances should never be used

Pipework around sinks must be bonded and earthed.
This is called bonding

				
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posted:11/7/2011
language:English
pages:6