Thread: Water pipe ground question

Is it ok for the copper water supply piping NOT to be part of the grounding electrode system as long as the water lines are bonded to the existing grounding components? Or, is it acceptable to include the water piping as part of the grounding electrode system and make the connection somewhere other than within 5 feet of the point of entry if you can confirm that the path to ground is not broken. I am asking this question because often times the metal water pipes are not included as part of the grounding system and to retrofit sometimes involves major tear out of ceilings, etc. and major $$$'s.

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Greg,

Clarification is needed.

1) The *underground* metal water pipe (typically the water service pipe for older homes) may be used as part of the grounding electrode system, provided there is at least 10 feet of it buried underground, and to do so, it *must be bonded to within 5 ft*of the point of entrance into the building for that to be used as such.

Also, when using an underground metal water pipe as a grounding electrode, it *must be* supplemented with another grounding electrode - it cannot be used of and by itself.

2) The metal water piping *system* "installed in or attached to" a building is required to be bonded to "the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used".

In 1), the metal water pipe is being used as part of the grounding electrode system, whereas in 2), the metal water piping system is bonded to the grounding electrode system.

1) The *underground* metal water pipe (typically the water service pipe for older homes) may be used as part of the grounding electrode system.....

So in other words....It MAY be included but does not have to be included as part of the grounding electrode system. But no matter what, it has to be bonded to the electrical system.

This is supposing there are other grounding electrodes.

Originally Posted by Greg Jenkins

1) The *underground* metal water pipe (typically the water service pipe for older homes) may be used as part of the grounding electrode system.....

So in other words....It MAY be included but does not have to be included as part of the grounding electrode system. But no matter what, it has to be bonded to the electrical system.

This is supposing there are other grounding electrodes.

No, I should have stressed or stated that differently:

*IF* it is present ... *it must be tied to the grounding electrode system*.

What I was saying was that 'it may be used' *if present* - wait, that does not sound right either ... trying it again ... on older homes, *you may* find an underground water pipe ... and that it was used as part of the grounding electrode system, which is okay *IF* bonded to the grounding electrode system outside or within 5 feet of the point of entrance into the building.

In fact, *it may be* 'the only grounding electrode' present on older homes.

There, I think that is a better way to state it.

Thanks Jerry - you confirmed what I already believed (and have been calling out on inspections). I also went back and read Section E3508 Grounding Electrode Sytem in the IRC. I just needed a refresher course. I recently had an agent tell me my inspection was going to "kill the deal". The water pipe ground (lack of) was one of the electrical conditions I called out. I guess I was just looking for some reassurance.