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Electric Grounding Grounding down to earth comments RARS Meeting – August 2009

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					"Grounding: down to earth
      comments!"

 RARS Meeting – August 2009
Reasons for Grounding

 • Safety
 • Performance
Safety

•   Minimize touch potential.
•   Provide a low impedance path to clear
    phase to ground electrical power circuit
    faults.
Performance

•   Equalize potential differences to prevent
    or mitigate unwanted coupling, instability,
    radiation, etc.
Reasons for Grounding a Radio Station

•   Minimize touch potential.
http://www.nppa.org/professional_development/self-training_resources/look_up_report/Touch%20Potential-1.jpg
Reasons for Grounding a Radio Station

•   Minimize touch potential.
•   Equalize potential differences to prevent
    or mitigate unwanted coupling, instability,
    radiation, etc.
Reasons for Grounding a Radio Station

•   Minimize touch potential.
•   Equalize potential differences to prevent
    or mitigate unwanted coupling, instability,
    radiation, etc.
•   Prevent damage to the station from
    lightning discharges.
                   The Basics
E (voltage) = I (current) x R (resistance)
• If I = 0, then E = 0.
• If R = 0, then E = 0.

If E1 = E2, then the potential difference between E1
     and E2 is 0, therefore the current that flows in a
     resistance between E1 and E2 is 0.
Bonding
To prevent station damage, one must equalize
    voltage differences caused by lightning
    discharges.

Bonding is the means by which the potential
   difference between conductive elements is made
   to be 0 volts.
Grounding
When either an individual conductive element, or a
  system of elements, is at the same potential
  difference as the earth, they are said to be
  grounded and at equal-potential to the earth.

Grounding is achieved through bonding of a system
   of elements to a grounding electrode.
Grounding Electrode
A conductive element that is in contact with the
   earth is a grounding electrode.

Typical examples of a grounding electrode:
• Ground rod.
• Metallic underground water pipe.
• Ground ring.
http://www.dranetz-bmi.com/pdf/groundtesting.pdf
Grounding Electrode Conductor

The wire that connects (bonds) the ground rod to
another element of the grounding system.
  Building a Grounding System
• Grounding Electrode (reference to earth)
  Building a Grounding System
• Grounding Electrode (reference to earth)
• Grounding Electrode System
  Building a Grounding System
• Grounding Electrode (reference to earth)
• Grounding Electrode System
• Grounding Electrode Bonding Conductors
    Building a Grounding System
•   Grounding Electrode (reference to earth)
•   Grounding Electrode System
•   Grounding Electrode Bonding Conductors
•   Grounding Electrode Conductor
    Building a Grounding System
•   Grounding Electrode (reference to earth)
•   Grounding Electrode System
•   Grounding Electrode Bonding Conductors
•   Grounding Electrode Conductor
•   Main Ground Bar
    Building a Grounding System
•   Grounding Electrode (reference to earth)
•   Grounding Electrode System
•   Grounding Electrode Bonding Conductors
•   Grounding Electrode Conductor
•   Main Ground Bar
•   Bonding Conductors
http://www.astrosurf.com/luxorion/qsl-lightning-protection4.htm
Questions
                       References
• http://www.nppa.org National Press Photographers Association
• http://www.dranetz-bmi.com Dranetz-BMI
• http://www.astrosurf.com French Astronomy Web-site
                      To learn more:
Lightning Protection for the Amateur Radio Station –
Ron Block, KB2UYT
• http://www.arrl.org/tis/info/pdf/0206056.pdf Part 1, QST, Jun. 2002
• http://www.arrl.org/tis/info/pdf/0207048.pdf Part 2, QST, Jul. 2002
• http://www.arrl.org/tis/info/pdf/0208053.pdf Part 3, QST, Aug. 2002

Getting Down to Earth
http://www.biddlemegger.com/biddle-ug/GettingDownToEarth-MC.pdf
One of numerous application guides found at BiddleMeggar.com

All About Lightning
http://www.astrosurf.com/luxorion/qsl-lightning-protection4.htm
                        To learn more:
MIL-HDBK-419A - MILITARY HANDBOOK
GROUNDING, BONDING, AND SHIELDING FOR ELECTRONIC
  EQUIPMENTS AND FACILITIES
VOLUME 1 OF 2 VOLUMES - BASIC THEORY
VOLUME II OF 2 VOLUMES – APPLICATIONS

TM 5-811-3/AFM 88-9 - TECHNICAL MANUAL
ELECTRICAL DESIGN - LIGHTNING AND STATIC ELECTRICITY
  PROTECTION

Available for FREE download from: http://www.everyspec.com/

And http://140.194.76.129/publications/
Publications of the Headquarters, United States Army Corps of Engineers

				
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Description: Many people have heard of the term “grounding”, but few fully understand its meaning and importance. Sometimes, even experienced electricians do not treat grounding as a serious issue. The impact of an incorrect or absent grounding ranges from noise interference, resonance or humming during the use of electrical equipment to the worst case where electricity leakage through the chassis causes personal injury or damage to instrument components. Grounding, therefore, is a very practical issue that should be dealt with properly. For those who operate electrical equipment frequently, a complete understanding of grounding theories and applications is necessary in order to become a best-in-class technician.