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Old 10-16-2008, 03:17 PM   #1
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grounding multiple service panels


I've got 6 125 amp panels that are individually grounded to copper water pipe. The pipe does not go to ground. The original metal water pipe has been replaced with pvc. There have been several leaks at the pvc/metal connection. Several "water people" have said the leaks are caused by electralysis from the grounds. We want to remove them from the copper pipe. It looks like each panel has an additional ground wire going to a driven ground. I want to put the 6 wires on a buss bar and add one to the bar and take it to a driven ground. I don't think I should just unhook them. Do I have the right plan?

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Old 10-16-2008, 03:44 PM   #2
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grounding multiple service panels


What you have now is correct. DO NOT remove the water bonds!!!!! Your water people are looking for a scapegoat.

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Old 10-16-2008, 04:54 PM   #3
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There have been several leaks at the pvc/metal connection.
Then the water dept. needs to find out how a pvc connection is conducting electrolysis! Plastic is an insulator- not a conductor. Maybe they should be checking for pH levels in the water!
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Old 10-17-2008, 12:12 PM   #4
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grounding multiple service panels


I have to question the responses. If the water line is PVC, how can it be considered a compliant GEC connection? Doesn't the water line have to be metal and in contact with earth for at least 10"? Wouldn't these water bonds be useless?
It looks to me that his only bonding means is the electrodes and the piping is doing nothing.
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Old 10-17-2008, 12:37 PM   #5
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grounding multiple service panels


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Originally Posted by J.V.
Doesn't the water line have to be metal and in contact with earth for at least 10"?
Probably a typo, but 10 ft, no?

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There have been several leaks at the pvc/metal connection. Several "water people" have said the leaks are caused by electralysis from the grounds.
If the ground wire is connected to the copper using a steel clamp, there could be galvanic corrosion at the ground wire connection point, but it wouldn't have an effect at the PVC connection. Unless there is a steel fitting in between the copper and PVC. Then it still wouldn't be the fault of the GES.
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Old 10-17-2008, 12:56 PM   #6
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grounding multiple service panels


Absolutely. However, each panel has a second ground that goes into the wall behind it. I'm pretty sure they all go to a driven ground that is just outside this service room. I have not dug around yet, but I cannot find a second ground rod, which is current code. I will drive one if I don't find one. What we're addressing are those six wires connected to copper. Actually, each wire is very neatly connected to two different pipes. It may have been to code originally, because the water supply was probably metal. Now, the supply lines are PVC. They keep having leaks at the PVC to metal connection. A plumber and a water conditioner guy said the leaks are the result of electralsysis because of the grounds connected to the copper. The leaks are what they want to eliminate. I'm not sure the leaks are caused by the grounds to the copper. I'm going remove the wires from the copper and buss them together to a driven ground. It may be redundant, but easier than taking a wall apart to see where the other wires in the panel go. I also want to know if I can say that removing the grounds will affect the leaks.
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Old 10-17-2008, 04:42 PM   #7
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Originally Posted by J. V. View Post
I have to question the responses. If the water line is PVC, how can it be considered a compliant GEC connection? Doesn't the water line have to be metal and in contact with earth for at least 10"? Wouldn't these water bonds be useless?
It looks to me that his only bonding means is the electrodes and the piping is doing nothing.
They are doing nothing as far as a grounding electrode is concerned, but they are a valid water piping bond which is required.
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Old 10-17-2008, 08:15 PM   #8
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They are doing nothing as far as a grounding electrode is concerned, but they are a valid water piping bond which is required.
I never understood why I need to size this bond with Table 250.66 why cant the EGC from the well pump take care of this requirement?
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Old 10-17-2008, 08:27 PM   #9
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I never understood why I need to size this bond with Table 250.66 why cant the EGC from the well pump take care of this requirement?
That would be in line with the bonding of gas piping systems. The exception for gas piping systems, meaning allowing the furnace or boiler circuit ground to be the bond, states that the ground from the source "likely to energize" the piping can be used. This is mainly true with gas piping, but........
..... the water piping system in the house is much more widespread than the gas piping system. Also, consider the locations of parts of the water piping system. Kitchens and bathrooms can be very electrically dangerous if things are not right.
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Old 10-17-2008, 09:00 PM   #10
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That would be in line with the bonding of gas piping systems. The exception for gas piping systems, meaning allowing the furnace or boiler circuit ground to be the bond, states that the ground from the source "likely to energize" the piping can be used. This is mainly true with gas piping, but........
..... the water piping system in the house is much more widespread than the gas piping system. Also, consider the locations of parts of the water piping system. Kitchens and bathrooms can be very electrically dangerous if things are not right.
Most houses are plastic now anyhow, so its becoming a moot point for me.
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Old 10-18-2008, 01:22 PM   #11
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They are doing nothing as far as a grounding electrode is concerned, but they are a valid water piping bond which is required.
Required? I see most all residential in PVC today. If you don't have a metal water pipe, you have nothing else but the rods, right?
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Old 10-18-2008, 01:32 PM   #12
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grounding multiple service panels


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Required? I see most all residential in PVC today. If you don't have a metal water pipe, you have nothing else but the rods, right?
Well, in the case of the OP he specifically states copper piping. When I said they were required I was directing that at the OP.

In this case the rods and the water piping,they are two very different things. Bonding and grounding electrodes are not the same thing. Unless of course the water pipe is also being used as an electrode, then the water bond is inherent via the GEC.

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