Purpose of GEC

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Originally Posted by rattus View Post
.The GEC is meant to protect against electric shock.
How? Aside from tripping the breaker.

First off, I was talking about the EGC, not the GEC--my first mistake of the year.

Ohmic or capacitive leakage in a washing machine for example can make the cabinet hot unless an EGC is connected. You know that.

Quote:
Originally Posted by rattus View Post
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.

That's why I say that an EGC protects wiring but endangers people.

Don't see that at all.

Quote:
Originally Posted by rattus View Post
.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.
Not if the fault is a human.

Faults are inhuman, or is it inhumane?
 
rattus said:
Ohmic or capacitive leakage in a washing machine for example can make the cabinet hot unless an EGC is connected. You know that.
Click to expand...

Yes sir, I do.

Originally Posted by rattus View Post
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.
Click to expand...

That's why I say that an EGC protects wiring but endangers people. And don't forget about a neutral problem.

rattus said:
Don't see that at all.
Click to expand...

Suppose the egc fails. Or the there simply just isnt a return connection to the breaker for whatever reason.

I thought I knew you better than this Rattus? Are you sure you can't see a health risk here?

Originally Posted by rattus View Post
.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.
Click to expand...

Not if the fault is a human.

rattus said:
Faults are inhuman, or is it inhumane?
Click to expand...

Rattus, would you please stop making me have to repair your posts in order that I can respond to them. :grin:

It is nice to argue with you again, I have always considered you a friend.
 
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physis said:
Yes sir, I do.

That's why I say that an EGC protects wiring but endangers people. And don't forget about a neutral problem.

Suppose the egc fails. Or the there simply just isnt a return connection to the breaker for whatever reason.
Click to expand...

Sam, the absence of an EGC is a danger. I still don't see that it protects wiring. Breakers do that.
 
physis said:
The EGC is a fault path back to the breaker, without that or the grounded conductor the breaker is useless.
Click to expand...

Of course Sam, without a return path, there would be no excessive current. Also, the return path might be through building steel or copper plumbing.
 
boboelectric said:
I still beileve that ground rods do not add to any grounding because of resistance,Only for high current,high voltage fault faults.
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That would not be true because you because you can actually measure a decrease in resistance by adding additional ground rods.
 
bob said:
That would not be true because you because you can actually measure a decrease in resistance by adding additional ground rods.
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There is a point of diminishing returns. Also, real life forces us to deal with impedance, not resistance. True low impedance grounding systems will use copper strap, not wire, for conductors.

EGCs that use wire for conductors have only one function and that is to provide a path back to neutral that only has current flow during a fault.

The NEC requirements for a grounding system have little to do with lightning protection, although a good grounding system is essential for effective lightning protection.
 
boboelectric said:
I still beileve that ground rods do not add to any grounding because of resistance,Only for high current,high voltage fault faults.
Click to expand...

Grounding literally means to connect a given voltage to earth. It's evolved into meanings things like tying part of a transfomer secondary to a point that's called ground or common. The same concept applys to batteries an other powerer supplies as well.

That's because if two different power sourses aren't connected in some way, they call that floating, then you can have who knows what voltage between one and the next, and that can be dangerous.

Earth grounding has nothing to do with fault clearing, and if it does, that in itself is a hazard. Cause now the dirt people are standing on is energized. And with all the "bonded" metal around, that's dangerous.

One of the moderators here would like to change some of the NEC language to more clearly reflect the difference between grounding and bonding and I agreee with his efforts. The current wording not only leads to, but in my opinion, sort of promotes some degree of confussion.
 
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K8MHZ said:
True low impedance grounding systems will use copper strap, not wire, for conductors.
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Soooo... a copper strap has less impeadence than a copper wire???

I'm guessing dimensions or conductor protection aren't as important here?

I consider insulated stranded wire to be far more durable than a bare flat strap. Especially given where you'll find a lot of this stuff.
 
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