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#93460 05/31/05 04:39 PM
Joined: Dec 2004
Posts: 1,064
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No it doesn't.
250.50 states if they are available, the must be bonded.
250.50 doesn't state a underground water pipe must be used as a ground electrode.

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#93461 05/31/05 04:40 PM
Joined: Aug 2003
Posts: 1,374
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Better still, 2005 NEC 250.50 says "if present", they must be used.

Sorry, but I think you are worng. I am with Bob on this one.


Ryan Jackson,
Salt Lake City
#93462 05/31/05 04:49 PM
Joined: Dec 2004
Posts: 1,064
D
Member
I haven't got the 2005 code book, maybe they reworded it.

I am going by the wording of the 2002 book.

It's not who's right or wrong, it's just the wording that could throw you off.

It's like Emt. It is PERMISSABLE to use it as a ground, You don't have to, you are allowed to pull and EG in the EMT. But you could use it.

Does the 2005 book state the water pipe has to be used as an electrode or does it still state it has to be bonded?


Dnk.......

#93463 05/31/05 04:56 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Dnk you are really surprising me on this one, I thought this was a clear one.

Quote
250.50 states if they are available, the must be bonded.

250.50 doesn't state a underground water pipe must be used as a ground electrode..

Yes 250.50 states it must be bonded.

Bonded into the grounding electrode system.

Then 250.24(C) requires this grounding electrode system to be connected to the grounded conductor by means of a grounding electrode conductor.

If a water pipe is present that meets the criteria of 250.52(A)(1) it must be used along with any other present electrodes as a grounding electrode.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#93464 05/31/05 05:15 PM
Joined: Aug 2003
Posts: 1,374
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Moderator
It does say bonded...."bonded together to form the grounding electrode system.


Ryan Jackson,
Salt Lake City
#93465 05/31/05 07:46 PM
Joined: Feb 2003
Posts: 687
A
Member
I allready posted about Bufflao Grove IL does not allow grounding rods. Why? They don't know it's just allways been that way sence the last electrical inspector.

Tom

#93466 05/31/05 09:13 PM
Joined: May 2005
Posts: 23
T
Member
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.

It doesn't say "shall be permitted to be bonded", it says it "shall be bonded." Period. By the NEC, all the available grounding electrodes shall be used.

See 90.5 for a refresher on mandatory versus permissive language. [Linked Image]

#93467 05/31/05 10:00 PM
Joined: Jan 2005
Posts: 5,316
Cat Servant
Member
I think the confusion comes from the change in how we look at the water pipe.

In the old days, the water pipe was seen as the "grounding electrode," the point where lost electricity returned to earth.

That is no longer true. Today, the water pipe is nothing more than another piece of metal, that we connect to the ground wire network to "drain" it of any "lost" electricity, return that electricity to the panel, and let it return to earth through the ground rod.

In very simple terms, this is the difference between "grounding" and "bonding".

We used to "ground" through the pipe.

We now "bond" the pipe.

#93468 05/31/05 10:46 PM
Joined: Feb 2005
Posts: 693
L
Member
Again, metal water piping must be bonded in all cases, and may double as a grounding electrode if certain circumstances permit.


Larry Fine
Fine Electric Co.
fineelectricco.com
#93469 06/01/05 03:05 AM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
If you blind yourself to everything else and read this: "250.53(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(7)."

It might sound as thought an underground water pipe were the MAIN GROUND electrode, all others were extra.

As to the original question, I can not think of anywhere that would not want it bonded, if not part of the electrode system.

And only time I think it would not be considered part of the electrode system is if it had a water meter less than 10' away.

As far as local practice:
Water GEC is sized for service - always!
(2) rods as supplimentary electrodes
Bonding:
Load side of gas meter bonded to service or electrode system.
And hot water at the point nearest origin and continuous to the electrode system cold water at nearest point. (Like at the water heater.) Used to hit the gas there too, until a few years back.

And yep, different places require different things as far as this goes.

Saw some commentary in the code about this:
Quote
There has always been uncertainty as to whether metal water piping systems should be used as grounding electrodes, so many years ago the electrical industry and the waterworks industry formed a committee of all interested parties to evaluate the use of metal underground water piping systems as grounding electrodes. Based on its findings, the committee issued an authoritative report on this subject. The International Association of Electrical Inspectors published the report, Interim Report of the American Research Committee on Grounding, in January 1944 (reprinted March 1949).
The National Institute of Standards and Technology (NIST) has monitored the electrolysis of metal systems, because a flow of current at a grounding electrode on dc systems can cause displacement of metal. The results of this monitoring have shown that problems are minimal.
Maybe they are still arguing about it somewhere?

[This message has been edited by e57 (edited 06-01-2005).]


Mark Heller
"Well - I oughta....." -Jackie Gleason
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