Bonding interior copper water piping

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infinity

infinity

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Recently I did a 200amp service in a dwelling with a PVC water main from a well. My intention was to bond the interior copper water piping system at the nearest point adjacent to the panel, about 5 feet away. The inspector told me to "treat the water main as if it were copper and bond the interior piping system with in five feet of the entrance of the PVC water main into the house". So after running 100 feet of #2AL across the basement he passed the installation.

My question is, couldn't the interior copper piping system been bonded at the nearest point to the service(five feet away) instead of by the method he required?
 
Re: Bonding interior copper water piping

Yes, there is no requirement to bond the interior metal water piping system at any particular location unless it is also being used as a grounding electrode. :D
 
Re: Bonding interior copper water piping

Originally posted by infinity:
The inspector told me to "treat the water main as if it were copper and bond the interior piping system with in five feet of the entrance of the PVC water main into the house".
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Because we all know that PVC pipe makes a great grounding electrode. :roll: Is this inspector out of his mind?

Maybe you will challenge him the next time he asks you to do something like this?
 
Re: Bonding interior copper water piping

You were correct. But its common to confuse the underground metal water pipe grounding electrode requirement in 250.52(A)(1) with the bonding requirement in 250.104. If the water pipe does qualify as a grounding electrode, then the connection does not have to be made within 5 ft.
 
Re: Bonding interior copper water piping

Tom
I think you meant if the cold water is not the grounding electrode, you are not required to make the connection within five feet of where it enters the building. :)
 
Re: Bonding interior copper water piping

Thank you all for the replies. I agree that the bonding could have been at any point on the interior piping system since the copper piping was not a grounding electrode. He didn't see it that way and was adamant about how he wanted it done. Some battles are worth fighting, some aren't.
 
Re: Bonding interior copper water piping

Originally posted by infinity:
Thank you all for the replies. I agree that the bonding could have been at any point on the interior piping system since the copper piping was not a grounding electrode. He didn't see it that way and was adamant about how he wanted it done. Some battles are worth fighting, some aren't.
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So now you can do it his way the next time too. :roll:
 
Re: Bonding interior copper water piping

And the time after that. And the time after that. And the time after that. And the time after that. And the time after that. Ad infinitum. :D
 
Re: Bonding interior copper water piping

like I have always said ask him for a code section, 250.52 (A) (1), says exactly what an electrode is and what you have is not. you should not have to waste your time & money on a non code issue.
 
Re: Bonding interior copper water piping

If you had a mike holt grounding and bonding book you can show him the appropiate picture.
 
Re: Bonding interior copper water piping

Downstream of a meter or other removable equipment grounding of interior piping is an equipment grounding function, not a grounding electrode function.

You should find an excuse for hooking up the well casing as a grounding electrode. It probably is already bonded to some extent by the equipment grounding wire for a submersible pump, but do you want that to get toasted some day?

I run the grounding electrode conductor straight to the street side of the meter if any. I then use split bolts or the equipment ground bus in the service equipment to bond the downstream pipes. I have also bonded subpanels to the interior pipes if the subpanel is far from the service.
 
Re: Bonding interior copper water piping

NEC-2005 250.112(M) Metal Well Casings. Where a submersible pump is used in a metal well casing, the well casing shall be bonded to the pump circuit equipment grounding conductor.
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I hope that the well casing isn't "probably" bonded to the pump; it's required. :D

What would happen if it were also used as a grounding electrode? I having trouble seeing if it would be a problem or not, having a #10 EGC and a #4 GEC going to the same well casing from a service and a subpanel?
 
Re: Bonding interior copper water piping

My concern is if a #12 or #10 equipment grounding wire is the only ground wire to the well casing and the well casing happens to be the best grounding electrode. An open neutral under some circumstances could be rather hard on that #12 or #10 wire. If this wire gets toasted then there is no ground for the pump.
 
Re: Bonding interior copper water piping

mc5w again this is a matter of what is required compared to your concerns.

We can 'what if' any electrical installation to the point where the only answer is not to use electricity.

90.1(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance will result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.
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The NFPA recognizes even if the code is followed to the letter 'stuff' ;) happens.

What size conductor would you like to see to the well casing.?

Rod, Pipe, or Plate Electrodes only require a 6 AWG regardless of service size.

Bob
 
Re: Bonding interior copper water piping

Bonding the pipes to a subpanel has several advantages:

1. Reduction of potential difference. The first time that I did this the well was at one side of a 60 foot long house and the service at the other end. For some reason the electrical inspector did not required a grounding electrode conductor from the service to where the copper tubing ran out to the well casing. I suspect that it was because the well was only 5 feet from the house and wel casings are still NOT a required grounding electrode.

2. In the instance mentioned above I had to bond the cold water, hot water, and hot water return pipes to each other. Extending the wires to the panel anticipated the 1993 NEC requirement that the cold water pipe could not be used as a ground bus. The subpanel was the nearest ground bus and in fact was the ONLY panelboard in this house.

3. Having redundant grounding paths does help.
 
Re: Bonding interior copper water piping

I suspect that it was because the well was only 5 feet from the house and wel casings are still NOT a required grounding electrode.
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250.52(A)(1) states that it includes the well casing in the term "Metal Underground Water Pipe." If there is five feet of soft copper pipe running out to the well, and five feet of well casing (most likely more), then that is an electrode per (A)(1).
 
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