Purpose of GEC

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Seems this is more complicated than I had thought. I'm content to install my GEC knowing it has something important to do with equalizing potential. Good catch on my #6 typo : )
 
wawireguy said:
Seems this is more complicated than I had thought. I'm content to install my GEC knowing it has something important to do with equalizing potential. Good catch on my #6 typo : )
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It is a very good question, the reason it's not a simple one is because the NEC essencially hides from it.

If you use 4 AWG you don't have to do nearly as much conductor protection.
 
bob said:
Read the article I posted.
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physis said:
No, It's totally not my first bar-b-que.
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Sam I skimmed over the article - it's not what you think it is, take a gander at it. I had all sorts of things to say, then I read the article, and then kinda just shrugged off the conversation. It all just comes down to different people looking at different aspects of the same principles, IMO.
 
George Stolz said:
Sam I skimmed over the article - it's not what you think it is, take a gander at it. I had all sorts of things to say, then I read the article, and then kinda just shrugged off the conversation. It all just comes down to different people looking at different aspects of the same principles, IMO.
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Hi George, I haven't seen you in a while. I hope you've been well.

I agree with you in the respect that it evolved outside of the OP, and that there are certainly different opinions on the function of grounding.

I apologize if I've offended you or anyone else.
 
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The history of the grounding rod (and 25 0hm impedance) go back to the days of wireline telegraphs. Modern testing shows that in most places in the US the ground rod does much of nothing used in residential electrical systems.

If you really want to understand grounding, the following site has many technical files on grounding and lightning:

http://www.polyphaser.com/technical_notes.aspx

The list starts out with data stuff but about half way down gets into grounding.

Polyphaser is the company that makes stuff that enables 911 radio facilities to stay on the air during lightning storms. Most of the time, anyway....
 
Whoa now!

Whoa now!

wawireguy said:
I just realized that I really don't understand what the GEC does. Does it act as lightning protection? #6 min for ground rods seems rather small for that. Does it "equalize" something so that lightning doesn't want to hit that point? Does it have something to do with the POCO transformer feeding the service? Seems like I should know the answer to this but I'm unclear on this..:confused:
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Seems this discussion has gotten out of hand. It is about the GEC, no single-point or multi-point grounding, or lightning either.

The GEC is meant to protect against electric shock. With metal cased appliances and power tools, it is possible to get a tingle or even a lethal shock due to leakage between the hot line and the metal case. The GEC shunts this current to the neutral/ground bus. If a fault occurs, then this shunted current will be enough to trip the breaker.

Plumbers especially were the victims of such shocks. Grounded cases, double insulated power tools, and GFCIs have greatly reduced this risk.

A few years ago, three prong receptacles were not required. Remember the bare grounding wires shipped with washers and dryers? Of course, they only worked if the outlet box was grounded.
 
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rattus said:
Seems this discussion has gotten out of hand. It is about the GEC, no single-point or multi-point grounding, or lightning either.
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GEC = Grounding electrode conductor = the conductor connecting the electrical system to dirt.

The GEC is meant to protect against electric shock. With metal cased appliances and power tools, it is possible to get a tingle or even a lethal shock due to leakage between the hot line and the metal case. The GEC shunts this current to the neutral/ground bus. If a fault occurs, then this shunted current will be enough to trip the breaker.
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That is the EGC = Equipment grounding conductor = The conductor bonding the non current carrying metal parts to each other and the electrical system.
 
iwire said:
It does not matter how many times it connects to the earth, if you have enough current feeding into the grounding electrode it will not remain at the same potentional as the earth a few feet away from it.
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AFACT, this discussion isn't about fault conditions. Under ideal conditions, there is 0 volts to earth at the main bonding jumper. Under nominal conditions, there should not be more than a few volts to earth at the bonding jumper.

iwire said:
I have no idea what your trying to get across here:confused:
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The point is earth grounding provides a voltage reference to the system under normal operating conditions.

Why is it that when someone mentions grounding, many automatically think shock-hazard reduction? That is not the only purpose for grounding... especially earth grounding.
 
There are several advantages to using this single-point design. For example, if a phase-to-ground fault occurs at a piece of equipment along the electrical distribution system, a relatively controlled low-impedance path is provided back to the source. The fault current has limited routes back to the source and does not have the opportunity to diverge to multiple paths, creating parallel circuits. If multiple paths were introduced, the fault current would divide itself among the paths based on the impedance of the circuits.
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Perhaps it is just my nature, but this is paragraph two of the article posted. This is nonsense.
 
physis said:
Perhaps it is just my nature, but this is paragraph two of the article posted. This is nonsense.
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I don't see the nonsense, does that mean I am nonsensical? :D

One path is better as far as stray current problems such as those that cost dairy farmers money.
 
iwire said:
I don't see the nonsense, does that mean I am nonsensical? :D

One path is better as far as stray current problems such as those that cost dairy farmers money.
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Are we talking about faults that last for minutes before tripping a breaker? And are we talking about using the earth as a fault clearing conductor?
 
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physis said:
Are we talking about faults that last for minutes before tripping a breaker? And are we talking about using the earth as a fault clearing conductor?
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I don't know anymore, I am starting to suspect each of us posting to this thread is talking about something different.
 
Smart $ said:
Why is it that when someone mentions grounding, many automatically think shock-hazard reduction? That is not the only purpose for grounding... especially earth grounding.
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I'm interested in grounding. Fire is another purpose.
 
iwire said:
I don't know anymore, I am starting to suspect each of us posting to this thread is talking about something different.
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You might be right Bob, :grin: , I've honestly lost track to some degree between last night and this morning.
 
rattus said:
.The GEC is meant to protect against electric shock.
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How? Aside from tripping the breaker.


rattus said:
With metal cased appliances and power tools, it is possible to get a tingle or even a lethal shock due to leakage between the hot line and the metal case.
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That's why I say that an EGC protects wiring but endangers people.


rattus said:
.The GEC shunts this current to the neutral/ground bus. If a fault occurs, then this shunted current will be enough to trip the breaker.
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Not if the fault is a human.
 
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... For example, if a phase-to-ground fault occurs at a piece of equipment along the electrical distribution system, a relatively controlled low-impedance path is provided back to the source.
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I would like this a lot if it was talking about an EGC
I don't know how much this has to do with the GEC

The fault current has limited routes back to the source and does not have the opportunity to diverge to multiple paths, creating parallel circuits. If multiple paths were introduced, the fault current would divide itself among the paths based on the impedance of the circuits.
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I think this would also be more appropriate when talking about the EGC.

There are always multiple paths, regardless of the bonding or grounding paths provided. Providing a good ECG will hopefully allow much more fault current to go through it, than goes through you.

I have often thought it might be safer in some ways to NOT ground the electrical service... but then if you got multiple faults, you might get the dreaded "hit by 240" :smile: I think maybe that's what some people are thinking about when they talk about "stabilizing".
 
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