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Thread: Equipotential grid

  1. #1
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    Equipotential grid

    Im in the process of doing a pool for a friend it's in ground with a plastic shell but the top has metal caps for pavers to sit on, when doing the perimeter bond do these caps need to be bonded as well , there are probably about 10-12 peices going around the whole pool there not continous, the caps are pretty much in the dirt , I'm thinking the perimeter grid probably takes care of this but not sure

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  2. #2
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    code says any metal within five feet of the pool.
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  3. #3
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    I agree.. A pita job but it needs to be done. I have to do gutters and metal handrails for a sunken in the deck hot tub. Sucks. Why would I want to take stray voltage from the ground and put it on the gutters?
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  4. #4
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    So the metal caps are not exposed or able to be contacted by a person and are separated by a permanent barrier the paving stones? Wouldn't 680.26(B)(7)Ex#1 cover this?
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  5. #5
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    Quote Originally Posted by Dennis Alwon View Post
    I agree.. A pita job but it needs to be done. I have to do gutters and metal handrails for a sunken in the deck hot tub. Sucks. Why would I want to take stray voltage from the ground and put it on the gutters?
    A little confused at what you are getting at with this, might just be choice of wording though.

    Intent of equipotential bonding isn't to "ground" the objects in question - it is to bond all objects in the vicinity of the pool user so they are all at same potential - we sort of don't care what potential they are in relation to "ground". The entire pool could be sitting there at 100 volts above ground, but a well installed EPB system will leave the pool users with no clue they are "energized".

    Now that much voltage still likely yields problems at the perimeter of the deck and near other bonded objects, but located away from the pool.
    Last edited by ActionDave; 06-05-18 at 03:14 AM. Reason: repair quote
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  6. #6
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    I've done several concrete pools. They have a metal track that mounts to the top for the liner to hang on. This track is very thin and will be covered with coping stones. The inspectors here make me bond this track. It's a pain because the track is not one continuous piece but several pieces placed end to end. They don't actually touch each other so they are not electrically continuous.

    What I have to do is install a lay-in lug, rated for direct burial, on each section then run a #8 solid conductor around the top of the pool. Then I run a jumper down to the "Halo" #8 that encircles the pool. (equipotential bond wire)

    I argued that the track will be covered with coping and can't be touched and the water is also bonded but made no head-way with the inspectors so I just do it on all pools of that type that I do.

    So to answer the OP's question, yes you need to bond the metal caps.
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  7. #7
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    Equipotential grid



    You have to bond them unless they meet these exceptions.


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  8. #8
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    Quote Originally Posted by infinity View Post
    So the metal caps are not exposed or able to be contacted by a person and are separated by a permanent barrier the paving stones? Wouldn't 680.26(B)(7)Ex#1 cover this?
    Yes there not exposed will be covered by pavers and mortar

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  9. #9
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    Quote Originally Posted by Little Bill View Post
    I've done several concrete pools. They have a metal track that mounts to the top for the liner to hang on. This track is very thin and will be covered with coping stones. The inspectors here make me bond this track. It's a pain because the track is not one continuous piece but several pieces placed end to end. They don't actually touch each other so they are not electrically continuous.

    What I have to do is install a lay-in lug, rated for direct burial, on each section then run a #8 solid conductor around the top of the pool. Then I run a jumper down to the "Halo" #8 that encircles the pool. (equipotential bond wire)

    I argued that the track will be covered with coping and can't be touched and the water is also bonded but made no head-way with the inspectors so I just do it on all pools of that type that I do.

    So to answer the OP's question, yes you need to bond the metal caps.
    I never done a pool, but even though they are not exposed, I would think it is still a good idea to bond them. Kind of no different then having isolated rebar in about same vicinity if it were concrete - seems to have a possibility of being able to introduce a voltage gradient if not bonded to other items and especially between two sections of it that are as you mentioned are all separate pieces.
    I live for today, I'm just a day behind.

  10. #10
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    Mortar is porous so therefore not a permanent barrier


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