My house, built in 1962, has one grounding electrode: the metal plumbing system. Doesn't
meet Code now, but I'm pretty sure it did in 1962. The grounding electrode conductor is
attached to the plumbing directly inside the point at which it enters from the outside -- pretty
much completely on the opposite side of the house from the electrical service entrance.
In conjunction with a renovation project completely unrelated to the electrical system, I'm
going to have to temporarily disconnect and possibly relocate the grounding electrode
I know that current Code:
(a) does not permit the metal water plumbing system to be the *only*
(b) does not require the metal water plumbing to be a grounding electrode *at all*
(c) requires that *if*
it is used as a grounding electrode, the conductor must be attached
within 5 feet of the point of entrance to the building; and
(d) does require it to be bonded to *other*
Here's what I propose to do:
(1) Sink a 10-foot grounding rod directly outside the service entrance, and connect an
appropriately-sized grounding conductor (AWG 4 for 200A service?) to it and the service
entrance panel. That will give me a grounding electrode other than the water pipes.
(2) Cut the existing grounding electrode conductor short, and bond it to the water pipes at
the most convenient location, about ten feet from the service entrance -- which is some forty
feet from the point at which the water pipe enters the building.
Am I correct in believing that this meets current Code?
Here's my reasoning: The connection to the water pipe is much more than the five-foot
minimum required if the water pipe is used as a grounding electrode -- but because the
system will be grounded to a grounding rod, *that*
is the grounding electrode, *not*
water pipes, which are merely *bonded*
to the grounding electrode.