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I received a competitive quote from an electrician to upgrade my home's service. He wanted to know where the water and gas lines entered the house because he said they needed to be bonded to the GEC within 5' of the entrance to the house. This surprised me, because another electrician providing an estimate had said nothing about it.

I believe the electrician was combining two separate requirements in the NEC. 250.68(C)(1), which states the 5' maximum if the water main is used as the GEC, and 250.104(B), which requires the pipes be bonded to the GEC if there is a possibility they'd become energized.

I asked them and the response was that because the pipes were in contact with the earth for more than 10' they were inherently part of the GEC and had to be bonded to the rest of the GEC, within the 5'.

Even if this were true, I would think the solution would be to simply isolate the pipes from the ground (by replacing a section by the entry with non-conductive pipe), instead of running bare copper all around the house to get to the pipe entry. Since I don't hear of this being done, I'm totally skeptical. Is the electrician correct?

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  • I take it your water and gas mains are metal, as well as your indoor piping? Commented Jul 28, 2021 at 1:45

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Yes the pipes do have to be bonded within 5’ of entry, so that electrician is knowledgeable of the code. This has been a standard since my apprenticeship in the 70’s.
Pipe in contact with earth for 10’ or more can be a grounding electrode but with all things new installation have to meet modern code. Old systems are grandfathered but changes must meet current code so the 5’ guy was correct and this has been code for 20+ years or more.

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  • Can you point to the code?
    – Jonathan K
    Commented Jul 28, 2021 at 2:19
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    Looks like 250.50. Thanks for the answer.
    – Jonathan K
    Commented Jul 28, 2021 at 2:22

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