Grounding: down to earth comments!

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"Grounding down to earth comments!"

• RARS Meeting August 2009

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Reasons for Grounding

• Safety
• Performance

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Safety

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

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Performance

• Equalize potential differences to prevent or
  mitigate unwanted coupling, instability,
  radiation, etc.

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Reasons for Grounding a Radio Station

• Minimize touch potential.

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http//www.nppa.org/professional_development/self-
training_resources/look_up_report/Touch20Potentia
l-1.jpg
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Reasons for Grounding a Radio Station

• Minimize touch potential.
• Equalize potential differences to prevent or
  mitigate unwanted coupling, instability,
  radiation, etc.

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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.

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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.

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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.

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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.

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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.

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http//www.dranetz-bmi.com/pdf/groundtesting.pdf
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Grounding Electrode Conductor
The wire that connects (bonds) the ground rod to
another element of the grounding system.
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Building a Grounding System

• Grounding Electrode (reference to earth)

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Building a Grounding System

• Grounding Electrode (reference to earth)
• Grounding Electrode System

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Building a Grounding System

• Grounding Electrode (reference to earth)
• Grounding Electrode System
• Grounding Electrode Bonding Conductors

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Building a Grounding System

• Grounding Electrode (reference to earth)
• Grounding Electrode System
• Grounding Electrode Bonding Conductors
• Grounding Electrode Conductor

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Building a Grounding System

• Grounding Electrode (reference to earth)
• Grounding Electrode System
• Grounding Electrode Bonding Conductors
• Grounding Electrode Conductor
• Main Ground Bar

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Building a Grounding System

• Grounding Electrode (reference to earth)
• Grounding Electrode System
• Grounding Electrode Bonding Conductors
• Grounding Electrode Conductor
• Main Ground Bar
• Bonding Conductors

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http//www.astrosurf.com/luxorion/qsl-lightning-pr
otection4.htm
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Questions
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References

• http//www.nppa.org National Press
  Photographers Association
• http//www.dranetz-bmi.com Dranetz-BMI
• http//www.astrosurf.com French Astronomy
  Web-site

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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/GettingDownT
  oEarth-MC.pdf
• One of numerous application guides found at
  BiddleMeggar.com
• All About Lightning
• http//www.astrosurf.com/luxorion/qsl-lightning-pr
  otection4.htm

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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