Grounding system explanations

Hi,
I'm looking for an illustrating sample of how grounding systems work? Better
with some wording (Electric hazards)or explanations.... Or any NEC
Handbooks on-line?
Thanks
Jack
Reply to
Jacky Luk
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Try to track down a copy of Soares Book on Grounding. It may be in the library. I don't think you will find it online.
Reply to
Greg
By far the best on the subject. You do not even need a current copy. The older copies will be fine for understanding
Reply to
SQLit
Check out
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Try to track down a copy of Soares Book on Grounding. It may be in the library.
Reply to
Alan Stiver, PE
The original Soares book was an excellent explanation of grounding. However, the new version revised and sold by the IAEI is completely different. I don't know why they still put Soares name on it because it looks like the work of some tech writers with Phil Simmons's blessings. Anyway, for some excellent diagrams try the IEEE Orange Book, Emergency and Standby Power. I have used this book's diagrams to teach grounding to engineers. It has some excellent diagrams and fault current paths for both properly grounded systems and improperly grounded systems including high impedance grounded systems that are rather common in industrial facilities.
Reply to
Gerald Newton
I guess that is an advantage of being old. I have some of the older versions too. I agree some of the newer versions spend more time talking about code changes than fundamentals. That is why a library copy may be better than a current one from IAEI for this application.
Reply to
Greg
040806 0855 - Jacky Luk posted:
You could look here:
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Reply to
indago
There exist two grounding systems sharing many wires. The first is for human safety. NEC is only concerned with human safety issues; not transistor safety. A bus bar inside breaker box is where all receptacle safety ground wires, neutral wires, other utility wires and pipes, and earth ground meet. Any electricity that gets into one of these wires or pipes is shorted back to breaker box and should trip a circuit breaker. This is accomplished as described by volts500 in a previous post entitled "Grounding Rod Info" on 12 July 2003:
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That is grounding for human safety. The second system is earthing for transistor safety. A figure taken from National Institute for Science and Technology demonstrates the principle. Remember that wire is not a perfect conductor. Electrical characteristics on one end of wire are not same on other. Even though breaker box ground and earth ground are interconnected, they are still separate grounds connected by an electronic component called wire. Which end of a wire the protector is located, and that all earthing must be at a single point both become important. Earthing is demonstrated to protect fax machine transistors:
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The grounding system shares same wires. National Electrical Code since 1990 has changed what is necessary to connect breaker box safety ground to earth ground (for human safety). That same change also is necessary to make grounding for transistor safety effective. All safety grounds (to water and gas pipes, metallic bathtub, AC electric, telephone, CATV, satellite dish) must make a connection to the single point safety ground in breaker box. All earth grounds (from AC electric, telephone, CATV, satellite dish) must make a connection that is short (less than 10 foot and not inside metallic conduit), direct (no sharp bends, no splices), and independent (grounding wires separated from other wires) to a single point earth ground. Concepts of earthing are discussed in the newsgroup misc.rural as: Storm and Lightning damage in the country 28 Jul 2002 Lightning Nightmares!! 10 Aug 2002
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and
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Generally, an earth ground is a safety ground that has been enhanced to perform both jobs.
Jacky Luk wrote:
Reply to
w_tom
facilities.
I was told recently that the last version was written my Mike Johnston. He was an City of Phoenix electrical inspector/supervisor then moved to Texas to join IAEI.
Reply to
SQLit

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