grounding water pipe

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Greetings,
I understand that I must ground my water pipe within 6 feet of where it enters the basement. My circuit breaker box is 40 feet away on the other side of the basement. Is there any reason why I cannot just insert another grounding rod near where the water pipe enters the basement and ground it there? Is there some requirement that the two grounding rods be tied together by anything but the water pipe?
Thank you for your time and energy, William
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Presumably your water pipe comes in through the ground; why isn't it grounded already? I must be missing something; I don't even know why you would want it grounded. Is this a plumbing or electrical issue?
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Greetings,
I think what the inspector means is that he won't count my grounding from the circuit breaker to the water pipe as a second grounding rod because it is grounded to the water pipe more than 6 feet from where the water pipe enters the building. What he actually said though was that the water pipe needed to be grounded within six feet of where it enters the building.
I called up to ask for clarification and it was reiterated that I needed to ground the water pipe within six feet of where it enters the building. This sounded like nonsense to me but I didn't want to argue with the inspector any more than I already was. Does this rule exist? Every word I say to this guy he somehow seems to turn into an argument in seconds so I don't want to get back into it with him. He is very clear on what he wants "GROUND THE WATER PIPE WITHIN SIX FEET OF ENTERING THE BUILDING" but it makes no sense to my little non-inspector brain.
Maybe there is a very good reason for it that I just don't understand.
Thank you for your time and energy, William

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William Deans wrote:

William As you can see by reading the section below the underground metal water pipe must be used as a grounding electrode. The piping is grounding the system rather than being grounded. If the interior water piping were metallic and the underground supply piping were not you would still have to bond the piping to the grounded service conductor. Bonding connections can be made at any convenient point in an interior metallic piping system. A grounding connection to underground metal piping must be made close to were the piping enters the building in order to reduce the chance of the grounding connection being isolated from the underground piping by later changes in the interior piping system. The conductor that is used to ground the grounded service conductor to the water piping must be number four AWG copper. The fact that it is over forty feet away is just tough luck.
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. (5) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less than 2.5 m (8 ft) in length and shall consist of the following materials. (a)    Electrodes of pipe or conduit shall not be smaller than metric designator 21 (trade size 3/4) and, where of iron or steel, shall have the outer surface galvanized or otherwise metal-coated for corrosion protection. (b)    Electrodes of rods of iron or steel shall be at least 15.87 mm (5/8 in.) in diameter. Stainless steel rods less than 16 mm (5/8 in.) in diameter, nonferrous rods, or their equivalent shall be listed and shall not be less than 13 mm (1/2 in.) in diameter.
This next section covers how the Grounding Electrode System is installed. As you can see it requires that the underground metal water piping be supplemented by one other electrode to guard against the possibility that the continuity of the underground metal water piping will be broken by future plumbing work.
250.53 Grounding Electrode System Installation. FPN:See 547.9 and 547.10 for special grounding and bonding requirements for agricultural buildings. (A) Rod, Pipe, and Plate Electrodes. Where practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level. Rod, pipe, and plate electrodes shall be free from nonconductive coatings such as paint or enamel. (B) Electrode Spacing. Where more than one of the electrodes of the type specified in 250.52(A)(5) or (A)(6) are used, each electrode of one grounding system (including that used for air terminals) shall not be less than 1.83 m (6 ft) from any other electrode of another grounding system. Two or more grounding electrodes that are effectively bonded together shall be considered a single grounding electrode system. (C) Bonding Jumper. The bonding jumper(s) used to connect the grounding electrodes together to form the grounding electrode system shall be installed in accordance with 250.64(A), (B), and (E), shall be sized in accordance with 250.66, and shall be connected in the manner specified in 250.70. (D) Metal Underground Water Pipe. Where used as a grounding electrode, metal underground water pipe shall meet the requirements of 250.53(D)(1) and (D)(2). (1) Continuity. Continuity of the grounding path or the bonding connection to interior piping shall not rely on water meters or filtering devices and similar equipment. (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). Where the supplemental electrode is a rod, pipe, or plate type, it shall comply with 250.56. The supplemental electrode shall be permitted to be bonded to the grounding electrode conductor, the grounded service-entrance conductor, the nonflexible grounded service raceway, or any grounded service enclosure.
The point of attachment of the Grounding Electrode Conductor is a local matter. Some electric utilities require that the connection be made in the meter enclosure while others specifically forbid this. Some utilities require that it be connected to the grounded service conductor immediately adjacent to the demarcation point. For an overhead service the demarcation point is the splices between the overhead service drop, which is owned and maintained by the utility, and the service entry conductors, that are owned and maintained by the building owner.
I hope that this answers your question if you have more just ask. -- Tom H
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Greetings,
You are right. I thank everyone very very much for their help. This is the post which clearly shows me the requirements set forth by the NEC requiring me to run an additional 40 feet of grounding wire in parallel with a 3/4" copper pipe to within 5 feet of where the water pipe enters the building. I am still a little worried about the inspector's "six feet" "ground the water pipe" wording but I am going to try this and see what he says when he comes back.
You guys are great, William

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The water pipe must be grounded in case a live wire contacts it somewhere, causing a possibly lethal hazard for the plumber.
It may not be well grounded already even if the underground pipe outside the building is metal: soil, even when wet, is not a wonderful conductor. And who knows whether the pipe outside *is* even metal.
Perce
On 02/11/05 06:49 pm toller tossed the following ingredients into the ever-growing pot of cybersoup:

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Greetings,
The water pipe is connected to the grounding bus but not within 6 feet of where it enters the house. Why the 6 foot rule? As you say who knows whether the pipe outside *is* even metal?
William

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Why the six-foot rule? Electrical impedance, that's why.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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Greetings,
In this case Electrical impedance will be higher by routing the current through a 4 AWG wire instead of the lower impedance 3/4" Cu pipe. That doesn't mean it isn't why the rule is written that way-- only that in my case it shouldn't matter.
William
wrote:

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This is Turtle.
Some supply water service coming to the houses can be PVC pipe and will not ground the house piping system. So you ground it because of this reason.
TURTLE
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You're missing the point about this. The idea is not that the water pipe needs to be grounded (it already is, by virtue of being buried in the ground). The point is that the electrical code requires that metal water piping be bonded to the grounding electrode(s) for the electrical service to ensure that there cannot be any voltage differential between the plumbing and the electrical safety ground. Verify this with the inspector before doing anything, but I imagine what he means is that you need to have the grounding bus in your electrical panel connected to the water pipe, within six feet of where the water pipe enters the building -- most readily accomplished by running an appropriately-sized copper wire from the panel to within six feet of where the water pipe comes in.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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Greetings,
The water pipe is connected to the grounding bus and the grounding bus is connected to a grounding rod -- all within 3 feet of the circuit breaker. I have jumpers over the hot water meter and between the cold and hot pipes to/from the hot water heater.
Hope this helps, William
wrote:

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So I still don't get it -- where does it say this thing about the 6 feet in the NEC or plumbing codes?
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Doug is absolutely correct. The reason they want it connected close to the point the water pipe enters the building is to prevent fault currents from hurting anyone if a fitting along the pipe gets disconnected. Which is the same reason you install a jumper around water meters
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Greetings,
I understand your logic for why they want it connected -- and it already is connected with 4 awg solid copper -- but why must it be connected within 6 feet of where it enters the house? The water enters the house on the opposite side of the basement from where the electrical comes in. There is a water-pipe which runs right by the circuit breaker. Why run a 40 foot grounding wire when a 3 foot will do?
William
wrote:

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William, if you attach the wire to the pipe close to the electric panel and someone like a plumber,disconnects the pipe between your ground wire and where the pipe enters the house, and there is a fault current, the plumber can get electrocuted. I know there are a lot of if's here, but that's the reason
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Greetings, Does it actually say that somewhere in the NEC, etc? I don't want my code inspector making up code to enforce as he goes along. You are allowed to ground receptacle outlets to pipes when you replace a non-grounding receptacle outlet with a grounding one. Why don't the plumbers freak out about that? If the plumber disconnects the pipe between recepticle ground and the rest of the plumbing system the same problem could occur.
William
wrote:

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You may be correct, I think John gave you the exact code. Where I live, it doesn't matter if its code or inspectors interpretation of code. You need a certificate and the inspector hold it
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Greetings,
The code section that John quoted did not appear to establish a requirement for me to ground to the water pipe within 5/6 feet unless I wanted to use the water pipe as part of the grounding electrode system which I don't think I need to do. I already have a grounding rod and the service is 100 amps. Is there a section within the NEC which requires this?
William
Article 250.52(A)(1) of the 2005 NEC: ..... "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."
William
wrote:

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Yes, there is. Article 250-81(a) in the 1993 Code (which is all I have at hand at the moment) *requires* that metal water piping be bonded to the grounding electrode system. Whether or not you "want" to use the water pipe as part of the grounding electrode system is immaterial: the Code *requires* it.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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