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Thread: Bonding Water Pipes

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    Bonding Water Pipes

    I’m changing a residential service entrance from a 200 amp overhead to underground. Because the underground will enter the basement not near the existing main panel I am installing a main breaker at the new meter location. This of course will require four conductors be run from the new main to the existing panel and the panel will be converted to a sub-panel.

    My question is about the existing bond wire to the water line. The water line is not a grounding electrode. It is a plastic water line into the house. The bond wire is run from the metal pipe to the old main panel and connects to neutral. Am I correct that this wire does not have to be extended the the new main, and am I correct that it needs to just be moved to the equipment ground bar of the existing panel?

    On a similar subject, what gets bonded when there are multiple runs of plastic and metal water pipes all over a house. In other words the metal pipes are not continuous. I see this on residential jobs that have had multiple renovations over time.

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    In the first example, I believe the water pipe bond must be moved to new disconnect, regardless of the water pipe's qualification as an electrode.

    In the second, bonding of segments is not required, but is permissible. Now, how to determine what is and is not merely a segment?
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    A metal piping "system" requires bonding, if you do not have a complete system no bonding required.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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    Run a new #4 cu to the old metal water line . Even if it is not being used for water any more. It should be terminated to the main service disconnect. Therefore it wouldn't matter if it goes to the ground bar or the neutral as they are still connected in the main service. See 250.52 (A), etc...
    (If the old metal water line is not there any more, then it's not required)

    For interior bonding see ...250.104 (A) and beyond

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    Quote Originally Posted by Buck Parrish View Post
    Run a new #4 cu to the old metal water line . Even if it is not being used for water any more. It should be terminated to the main service disconnect. Therefore it wouldn't matter if it goes to the ground bar or the neutral as they are still connected in the main service. See 250.52 (A), etc...
    (If the old metal water line is not there any more, then it's not required)

    For interior bonding see ...250.104 (A) and beyond
    An abandoned metal water pipe is no longer a water pipe electrode. It can still be used as an electrode, but now falls under "rods and pipe" category. Interior water piping that has been abandoned is no longer water piping either, therefore 250.104 (A) no longer applies to it. (B) could apply to it though, and if not likely to become energized isn't required to be bonded.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by LarryFine View Post
    In the first example, I believe the water pipe bond must be moved to new disconnect, regardless of the water pipe's qualification as an electrode.

    In the second, bonding of segments is not required, but is permissible. Now, how to determine what is and is not merely a segment?
    Agree, bonding must move to the new service disconnect. I think one must evaluate if you even have a metal piping system or not. Occasional isolating components likely need bonded around, but if there is significant amount of non conductive piping you may no longer have a metallic piping system. NEC doesn't really give any specifics and is mostly a judgement call IMO.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by mkgrady View Post
    I’m changing a residential service entrance from a 200 amp overhead to underground. Because the underground will enter the basement not near the existing main panel I am installing a main breaker at the new meter location. This of course will require four conductors be run from the new main to the existing panel and the panel will be converted to a sub-panel.

    My question is about the existing bond wire to the water line. The water line is not a grounding electrode. It is a plastic water line into the house. The bond wire is run from the metal pipe to the old main panel and connects to neutral. Am I correct that this wire does not have to be extended the the new main, and am I correct that it needs to just be moved to the equipment ground bar of the existing panel?

    On a similar subject, what gets bonded when there are multiple runs of plastic and metal water pipes all over a house. In other words the metal pipes are not continuous. I see this on residential jobs that have had multiple renovations over time.
    I would think you would have to move the existing bond wire to the meter disconnect.

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    Quote Originally Posted by mkgrady View Post
    I’m changing a residential service entrance from a 200 amp overhead to underground. Because the underground will enter the basement not near the existing main panel I am installing a main breaker at the new meter location. This of course will require four conductors be run from the new main to the existing panel and the panel will be converted to a sub-panel.

    My question is about the existing bond wire to the water line. The water line is not a grounding electrode. It is a plastic water line into the house. The bond wire is run from the metal pipe to the old main panel and connects to neutral. Am I correct that this wire does not have to be extended the the new main, and am I correct that it needs to just be moved to the equipment ground bar of the existing panel?

    On a similar subject, what gets bonded when there are multiple runs of plastic and metal water pipes all over a house. In other words the metal pipes are not continuous. I see this on residential jobs that have had multiple renovations over time.
    I agree with the others that this should have a #4 to the new main disconnect, however If you cant trace the old main bond wire all the way to the pipe I would leave it connected on one end. The reason is I recently was asked to troubleshoot a home that outlets tested for 'open ground'. I looked at a few outlets and they all had old cloth wire and a #12 THHN run separately as is allowed for grounding older two wire cloth wiring. I opened up the brand new panel that had just been replaced and I could see a old solid copper 'bond wire' was snipped off just above the panel. I reconnected it and wala' all the outlets were grounded again. My point is you don't know what was tapped off those old grounding electrode conductors over the years.
    Comments based on 2017 NEC unless otherwise noted.

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