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Grounding #93450 05/28/05 06:44 AM
Joined: Jul 2002
Posts: 103
J
jes Offline OP
Member
Is anyone aware of a jurisdiction where it is NOT common practice to use an underground metal water piping system (where present) as part of the grounding electrode system for a residence and rely soley on a driven rod? Likewise, any jurisdictions where the grounding electrode system is NOT bonded to the interior metal water piping system (where present)?
If so...WHY?

2017 / 2014 NEC & Related Books and Study Guides
Re: Grounding #93451 05/28/05 07:42 AM
Joined: Oct 2004
Posts: 265
D
dmattox Offline
Member
The 2002 code makes it clear that the cold water should be at a minimum be bonded and if 10' of metal in the ground shall be used as a grounding electrode.

250.50 requires that if available each item in 250.52(A)(1)-(6) shall be bonded together. Metal underground pipe is item 250.52(A)(1).

250.104 (A) requires bonding of metal water piping.

So any jurisdiction not using the cold water is violating the NEC. The workbook notes in 250.52(A)(1) that there has always been uncertainty about using the cold water, but that NIST has monitored the issue and found minimal problems.

Re: Grounding #93452 05/28/05 08:06 AM
Joined: Jul 2002
Posts: 103
J
jes Offline OP
Member
Just a P.S. folks, I know that the NEC requirements are...what I am wondering about is local practices that may vary. Thanks!

Re: Grounding #93453 05/28/05 08:08 AM
Joined: Oct 2004
Posts: 265
D
dmattox Offline
Member
Yes I know you know, I was just stating what the people would be violating if they didnt bond the metal water. Its very clear from the NEC to do so, so I don't think anywhere would say you shouldnt. Everywhere in SoCal you have to bond the cold water.

Re: Grounding #93454 05/28/05 08:31 AM
Joined: Jan 2002
Posts: 1,457
E
Electricmanscott Offline
Member
Ther are places that forbid this. Where? I don't know. But I am 100% sure that this is true.

Re: Grounding #93455 05/28/05 08:44 AM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
I have to go with Scott here, I have read on these forums before that certain water companies forbid using the water supply as a grounding electrode.

Where?

Sorry I do not remember.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: Grounding #93456 05/28/05 07:53 PM
Joined: Dec 2004
Posts: 1,064
D
Dnkldorf Offline
Member
Bonding of the metal water pipe is mandatory in the code book, both well water or municipal.

Using it as a ground electrode is not mandatory, code simply states it can be used as an electrode, but must be supplemented if used as an electrode.

At least that is the way I read it..

Dnk......

Re: Grounding #93457 05/28/05 08:03 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
Dnk

Quote
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 installed and used.

As far as the NEC is concerned if a metal water pipe exists on the premises that fits the criteria of 250.52(A)(1) it must be used. [Linked Image]

These areas that do not use it are either ignoring or amending the NEC.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: Grounding #93458 05/31/05 04:52 PM
Joined: Dec 2004
Posts: 1,064
D
Dnkldorf Offline
Member
Iwire,

I am aware of what is states.
It is the wording that throws you off.
250.52 States that a water pipe is PERMISABLE, does not state it is mandatory.

I assume, they do not mean you have to have one or use one, but it is permissable to use it as a ground electrode, if it is supplemented by another ground electrode.

Re: Grounding #93459 05/31/05 04:59 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
Quote
250.52 States that a water pipe is PERMISABLE, does not state it is mandatory

250.50 tells us it is mandatory to use each of the items in 250.52 if they are avialable.

It is not a choice.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
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