DS
>Why does the water line have to be used as an electrode? If some inspectors require this, that's fine. But does the NEC require this?
Yes the code does require the use of a metal underground water pipe as a grounding electrode if it exists. 250-50
>If the largest branch circuit that could energize the interior piping is 50 A, then I think that #6 bonding the interior piping is adequate.
Do you want to install what you think is correct, or what the code requires? If you were talking about other interior metal piping systems I would agree with your comment, but 250-104(a)(1) requires the bonding of an interior metal water piping system with a conductor sized per Table 250-66. If the undergound metal water pipe is used as a grounding electrode, then all that would be required to bond the interior piping would be a jumper at the water meter.
Don(resqcapt19)
