Grounding straps on water meters

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W_Tom is a long time, and well documented usenet freak troll. His bag is to post lengthy diatribes that contain enough true technical facts to sound legit, but then he goes over the edge and adds fantasy crap. Don't ever trust ANYTHING he posts. He's got a history of this that goes back for years. He's a very clever troll, but he's nonetheless a TROLL. He has posted advice that could easily KILL somebody. That's how he gets his jollys.
rusty redcloud
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Paul Franklin wrote:

I'm still trying to figure out what kind of grounding clamp is listed for use on plastic pipe... (in other words, how did they attach the meter jumper)
-Bob
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Bob,
There is a length of copper pipe between the plastic supply pipe and the meter. It is about a foot long and holds the shutoff valve. There also is a length of copper pipe from the meter to the connection with the internal PEX. It is about 3 ft long and has a tap on it.
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Paul et. al. That simply is not true. The US National Electric Code requires that underground metal water piping that is ten or more feet in length must be used a grounding electrode. It also requires that the any interior metal water piping be bonded to the grounded conductor of the electrical service.
"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. 250.52 Grounding Electrodes. (A) Electrodes Permitted for Grounding. (1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system." Copyright 2002 National Fire Protection Association
-- Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
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Article 250.52(D)(2):

Water pipe alone is no longer sufficient as the earth ground electrode. Water pipe (meeting additional criteria) can be part of a "grounding electrode system"; but is no longer sufficient AS the earth ground. Meanwhile, safety ground must bond to the water pipe to remove electricity from that pipe. Obviously, that safety ground would also become part of the earthing system. But that water pipe alone is no longer sufficient as the earth ground.
HorneTD wrote:

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w_tom wrote:

In the 2005 NEC this is 250.53. This is a "supplemental electrode". The water pipe is a great ground and is the grounding electode. The problem is it could be replaced by plastic in the future. Supplementary electrodes are protection against that possibility. Ground rod(s), which are commonly used as the supplemental ground, are not particularly good grounds. (A 25 ohm ground resistance is pretty funny.)

I have no idea what "removing electricity from the pipe" means.
Bud-- Master electrician
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tomkanpa wrote:

I have not seen anything like that, I live in Columbus, but I guess it is possible. I do suggest that you don't rely on plumbing for a good reliable ground in any home. If you need a true ground, put one in.
--
Joseph Meehan

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Assuming you get your electricity from a utility, there already is a "true" ground at the service entrace for power. The "network protector" of the telephone company is also connected to that ground.
If you have metal plumbing inside your home, it probably a good idea to bond that to your electrical utility ground.
Some of this stuff goes back to the old days when the water distribution system was metal and there just wan't any better ground than a water pipe. A tradesman might just automatically connect the meter jumper just because it is quicker to install a jumper than try to explain why a jumper isn't needed.
A similar thing happened with the electric utility ground system. The rule was that you only needed one ground rod is you could show that the resistance to ground was less than 25 ohms. Otherwise you needed two rods. It was quicker to put in two rods than test the first rod.

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