Knob & Tube and Cloth Shielded Wiring

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wrote:

You are simply wrong. The NEC agrees with me. Its dangerous and illegal to use cold water pipes for a ground, and has been for many years. You are a twit.
CWM
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Charlie Morgan wrote:

The CEC on the other hand explicitly allows (and in some cases mandates) grounding via metal cold water pipe.
In fact, if you have at least 10ft metal piping buried deep enough then it *must* be used as the service grounding electrode. This is acceptable without any additional artificial electrodes.
If the above is not available, we can also use a metal well casing, ground rods (at least 2), or concrete encased electrode under the building footings.
Chris
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Chris Friesen wrote:

Contrary to Charlie, the US-NEC rule is almost identical. The depth ("deep enough") doesn't matter. And the NEC requires a "supplemental" electrode only because a metal underground water pipe may be replaed by plastic at some time in the future.
The NEC does not generally allow connecting grounds to water pipes except within 5 feet of the water service entrance, which may be what Charlie is picking up.
-- bud--
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RBM wrote:

Then your code book is wrong. The purpose of attaching a ground to a water pipe is to ground the water pipe!
This protects the homeowner or plumber when dealing with a (possibly broken) electrical appliance near the pipes.
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Yes that's correct and if you had read the NEC 250.131c , you would find that by attaching the water line, and ground rods, etc, together it forms the grounding electrode system, and that a grounding conductor for a replacement grounding outlet ,can be attached to any part of that system, which includes the main cold water pipe extending no more than five feet into the building

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Charlie Morgan wrote:

Interesting you do not comment on RBM's code citation (which should actually be 250.130C). It explicitly permits attachment of a ground wire at "any accessible point on the grounding electrode system". That includes the first 5 feet of water pipe inside the building. RBM's statement is in acordance with the NEC. -- bud--
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wrote:

Incorrect interpretation. You need to take what the code says as a whole, not just select snippets without context. If you have your own well, you "might" be able to do that, and get it past an inspector, but if a water meter exists between that pipe and the part buried in the earth, you cannot. The pipe, if used, must be unbroken for a length of at least 10 feet in the earth and enter the houase without any breaks, joints, or devices in line.
CWM
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Charlie Morgan wrote:

If the water service pipe has 10 foot or more metal in contact with the earth it is required to be used as a grounding electrode, and the electrode connection may be made anywhere within 5 feet of the entrance. The water meter is required to be bonded. Ground wires discussed may be connected in the same 5 foot distance from the entrance point, as permitted in 250.130C. Grounds for phone and other communications protectors may be connected in the same 5 foot span, as for instance in 800.100B.
RBM's statement should be narrowed to the extent that if there is not 10 ft metal in contact with the earth the water pipe can't be used for other grounds, as discussed.
These are not code snippets without context. You have not provided any "code snippets" supporting your view. And you are arguing with 3 electricians (including Thomas Horne).
-- bud--
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Bud-- wrote:

Make that 4.
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This is turning out to be quite a black eye for the profession!
CWM
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Charlie Morgan wrote:

You're a funny guy Charlie! If you don't believe 4 electricians with a combined experience of over 100 years, will you believe a certified electrical inspector? If so, go ask him:
http://www.selfhelpandmore.com/homewiringusa/index.htm
If you don't believe him, then try alt.engineering.electrical
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Bud, thanks for the code correction, and the backup
Roy

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wrote:

His "backup" turned out to need a bit of corrections as well.
CWM

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From the 2000 IRC. ( the one my jurisdiction uses) :
E3508.1.1 Metal underground water pipe.Ametal underground
water pipe in direct contact with the earth for10 feet
(3048 mm) or more and electrically continuous to the points
of connection of the grounding electrode conductor and the
bonding conductors shall be considered as a grounding electrode.
Continuity of the grounding path or the bonding connection
to interior piping shall not rely on water meters or
filtering devices and similar equipment. A metal underground
water pipe shall be supplemented by an additional
electrode of a type specified in this section or in Section
E3508.2. The supplemental electrode shall be bonded to the
grounding electrode conductor, the grounded service-entrance
conductor, the grounded service raceway or any
grounded service enclosure.
Where the supplemental electrode is a made electrode in
accordance with Section E3508.2, that portion of the bond-
ing jumper that is the sole connection to the supplemental
grounding electrode shall not be required to be larger than
No. 6 copper wire or No. 4 aluminum wire.
--
Steve Barker


"RBM" <rbm2(remove this)@optonline.net> wrote in message
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Charlie Morgan wrote:

Well, the water pipe should be bonded; it just shouldn't be used as a primary ground. I agree, the correct method would be to use grounding stakes (several) and ground the panel that way and then bond the water pipe to the panel (as well as installing bonding jumpers around the meter and the HWH)
nate
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Yes the water pipes should be bonded, but they are not to be used to provide ground for anything else.
CWM
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Charlie Morgan wrote:

Can you explain why the US National Electric Code requires the underground metallic water piping be used as part of the Grounding Electrode System? It does you know, even when the entire interior plumbing system is non metallic.
--
Tom Horne

Well we aren\'t no thin blue heroes and yet we aren\'t no blackguards to.
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On Tue, 05 Dec 2006 04:29:23 GMT, "Thomas D. Horne, FF EMT"

It requires the metallic plumbing to be bonded. That is not the same thing as using the metallic plumbing as the point of ground source for other parts of the wiring.
CWM
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He'll never admit he's wrong. You might as well give up.
--
Steve Barker



"Thomas D. Horne, FF EMT" < snipped-for-privacy@mindspring.com> wrote in message
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Nate Nagel wrote:

If talking about grounding electrodes, a water pipe with at least 10 foot of metal in contact with the earth has been required for a long time to be part of the grounding electrode system. Particularly with a municipal metal water supply system, the water service pipe will have a much lower resistance to ground than ground rods, which are "supplemental" electrodes (required only because a metal water service may become plastic in the future). Mentioned somewhere in this thread, a concrete encased electrode (Ufer ground) is now required in new construction that has footings, and is used in place of a ground rod.
-- bud--
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