# "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 E 1 = E 2, then the potential difference between E 1 and E 2 is 0, therefore the current that flows in a resistance between E 1 and E 2 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