" wrote in news:7740703c-994c-402f-93a5-
:

On May 27, 6:26*pm, Doug Miller
wrote:
" wrote in news:afb2620e-b4
3c-48a2-8acf-
:

I would not an expert on the current code on this subject.
But I believe the above is incorrect. *I believe in the past
an underground water service pipe was allowed to serve
as the service ground.

It used to be... but hasn't been for at least 20 years.

So what, did all those older houses disappear or
have other grounding means added by magic?

No, all that's necessary is that it meet Code at the time of installation.

And I think even today it can serve
as part of it, but needs to be supplemented by other
grounding methods, eg ground rods.

Your understanding is incorrect. The *sole* reason that metal water pipes
need to be tied to
the electrical system's grounding electrodes is to ensure that the plumbi
ng system is at
ground potential, no matter what. The requirements for grounding the elec
trical system are
the same, whether the water pipes are metal or plastic.

Read:

NEC 2011 250.52 Grounding Electrodes
(A) Electrodes Permitted for Grounding
(1) Metal Underground Water Pipe

Under that section it says that an underground water
pipe that is 10 ft long is permitted for use as a
grounding electrode. It goes on to list the other permitted
electrodes as well.

Keep reading, and you will discover that the Code does *not* permit that to be the *only*
grounding electrode.


* The electrical distribution system will work just fine without a
water-pipe ground - a water-pipe ground in NO WAY influences the elect
ric
al
system.

It does if it's an older system and the water pipe is the
only earth ground.

That is no longer permitted in new construction.



The purpose of a water-pipe ground, and its only purpose, is to
protect the water system plumber from an electrical shock.

Per above, I believe that is incorrect.

Your belief is incorrect. HeyBub has it exactly right.

Even if what you say is true, which per NEC cited about
I don't believe is correct,

Only because you didn't read far enough... :-)

HeyBub would still be wrong
because he made no distinction between new services
and old ones that rely solely on the water pipe for
grounding. They have no other grounding electrode and
without the water pipe connection, the system would
be ungrounded and a danger.

Yes, and that's why, when the service from the municipal water supply is replaced with
plastic, the home *must* have an additional grounding electrode added.