"Chris Lewis" wrote in message
...
According to Tom Horne :

250.50 Grounding Electrode System.
...
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe.

....

There is no way you can read NEC section 250-50 that allows you to avoid
using the underground metal water piping as part of the grounding
electrode system.

Actually, one can show that very easily: note (A) above:

"Electrodes PERMITTED for Grounding".

Emphasis added.

It doesn't say it's "REQUIRED if present" for use as a grounding
conductor.


Probably because you CONVENIENTLY didn't quote 250.50, instead replacing it
with "..."
Quoted from NEC Section 250.50 Grounding Electrode System:
"IF AVAILABLE on the premises at each building or structure served, each
item in 250.52(A)(1) through (A)(6) SHALL BE bonded together to form the
grounding electrode system. Where NONE of these electrodes are AVAILABLE,
one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall
be used and installed."

250.52(A) Grounding Electrodes.
(1) Metal Underground Water Pipe.
(2) Metal Frame of the Building or Structure.
(3) Concrete-Encased Electrode
(4) Ground Ring
(5) Rod and Pipe Electrode
(6) Plate Electrode
(7) Other Local Metal Underground Systems or Structures.

Just so you won't also misinterpret (A)(7), 250.52(B) makes it clear that
metal UNDERGROUND gas piping systems or aluminum electrodes shall not be
used as grounding electrodes.

It says it _can_ be used as a grounding conductor (and elsewhere says if
used
it needs to be supplemented).

Elsewhere in the code it goes on to say that such pipes MUST be grounded.

Which means in the end it doesn't matter, because it's going to _act_ as
a grounding electrode, whether the NEC thinks of it as that or not.


Try to learn the difference between why interior metal piping is required to
be bonded to the electric grounding system and what constitutes a grounding
electrode system. So far, you are clueless. Try this:
http://www.iaei.org/products/books_02soares.htm


This whole argument is silly - it doesn't matter which way, because it's
going to be grounded (and in intimate earth contact giving decent duty
as an electrode) ANYWAY.
--

Yes, if you don't understand electric system grounding, it's easy to see how
you would think that the argument is silly.