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-   -   Circuit Panel Grounding Question (http://www.houserepairtalk.com/f9/circuit-panel-grounding-question-10475/)

jimmy4 12-06-2010 12:22 AM

Circuit Panel Grounding Question
 
Below is a grounding question regarding my circuit panel in my home. I tried to provide as much information as possible.

I have a 200A service panel in my home. It is located in the basement. The service enters the house underground. The electric meter is positioned on the exterior of the home and is approximately right behind the service panel (but above the surface of the ground).

The wiring in the house is exclusively via rigid conduit.

I checked the panel to see how the ground was connected and only saw a small "about 3 or so inches" rigid copper piece that was connected to the ground bar and then screwed to the back of the circuit panel box. I checked all other lines and didn't see any other type of grounding for the box on the exterior as well as around the basement, etc..

The home was built in 1987 (in IL) and originally had well water but then was converted to municipal water sometime later. The well is still active and used for outside irrigation purposes but the municipal water services the inside of the home (enters the home (basement) at a different location). I checked both sets of copper pipe thoroughly and saw no grounding clamps/wiring on either.

It appears that the only type of grounding for the panel is the small copper piece described above. My questions are as follows:
1) is that, in fact, the ground for the home?
2) if it is, is that sufficient?
3) if not, should I be looking for something else not described above?
4) if "yes" to #3, what should I be looking for or what needs to be done to properly ground the panel/home.

Hope this is enough information to answer my questions.

Thanks in advance.

handyguys 12-06-2010 11:40 AM

I'm not really picturing what you describe. I think what you should see is a ground rod outside, its about 8 feet long, pounded into the ground near the meter. From there you would have a copper wired come into the house, again near where your electric enters, and then into the panel. Here is a picture I found online
http://www.nachi.org/images08/grounding-rod-clamp.jpg

ajaynejr 01-28-2011 09:52 AM

I think your service entrance tube, assuming it is metal, is your "grounding electrode".

Normally all the pieces of a rigid conduit system, being screwed together, are considered bonded to one another. Chicago and a few other cities require conduit throughout for home wiring.

To qualify as a grounding electrode, a metal cold water pipe must be bare and buried for at least ten feet. Gas pipes do not qualify.

When something else is your grounding electrode, the plumbing system must be bonded to it using #6 copper wire. I think the wire can be clamped to the nearest point on that portion of conduit in line from the panel to the grounding electrode.

Except, when the water pipe qualifies as a grounding electrode itself, run a #4 copper wire to within 5' of where it exits the house if your electrical service is greater t han 100 amps.

speedy petey 01-29-2011 11:27 AM

My comments in red.
Quote:

Originally Posted by ajaynejr (Post 53541)

When something else is your grounding electrode, the plumbing system must be bonded to it using #6 copper wire. I think the wire can be clamped to the nearest point on that portion of conduit in line from the panel to the grounding electrode.
Typical bonding conductors for a 100A service would be #8cu or #4cu for a 200A service.

Except, when the water pipe qualifies as a grounding electrode itself, run a #4 copper wire to within 5' of where it exits the house if your electrical service is greater t han 100 amps.
Same sizes as above apply.


donaldr 06-01-2011 11:16 PM

Put a # 4 on the metal water piping and a #4 on the ground rod( use copper)


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