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"Grounding: down to earth comments!"

"Grounding: down to earth comments!"

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"Grounding: down to earth comments!"

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  1. "Grounding: down to earth comments!" RARS Meeting – August 2009

  2. Reasons for Grounding • Safety • Performance

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

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

  5. Reasons for Grounding a Radio Station • Minimize touch potential.

  6. http://www.nppa.org/professional_development/self-training_resources/look_up_report/Touch%20Potential-1.jpghttp://www.nppa.org/professional_development/self-training_resources/look_up_report/Touch%20Potential-1.jpg

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. http://www.dranetz-bmi.com/pdf/groundtesting.pdf

  14. Grounding Electrode Conductor The wire that connects (bonds) the ground rod to another element of the grounding system.

  15. Building a Grounding System • Grounding Electrode (reference to earth)

  16. Building a Grounding System • Grounding Electrode (reference to earth) • Grounding Electrode System

  17. Building a Grounding System • Grounding Electrode (reference to earth) • Grounding Electrode System • Grounding Electrode Bonding Conductors

  18. Building a Grounding System • Grounding Electrode (reference to earth) • Grounding Electrode System • Grounding Electrode Bonding Conductors • Grounding Electrode Conductor

  19. Building a Grounding System • Grounding Electrode (reference to earth) • Grounding Electrode System • Grounding Electrode Bonding Conductors • Grounding Electrode Conductor • Main Ground Bar

  20. Building a Grounding System • Grounding Electrode (reference to earth) • Grounding Electrode System • Grounding Electrode Bonding Conductors • Grounding Electrode Conductor • Main Ground Bar • Bonding Conductors

  21. http://www.astrosurf.com/luxorion/qsl-lightning-protection4.htmhttp://www.astrosurf.com/luxorion/qsl-lightning-protection4.htm

  22. Questions

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

  24. 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

  25. 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