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Thread: grounding and bonding xfmrs

  1. #1
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    grounding and bonding xfmrs

    I know how to do this but I cannot find all of the code articles about it. My biggest question is on the gec. So it goes to xo, and must be bonded where it enters the xfmr case right? I have read about and have seen special connectors that create a bond where your gec enters the case but cannot find the code article on it. thanks

  2. #2
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    Welcome to the forum.

    250.30. You can bond the XO inside the transformer or inside the first disconnect and your GEC lands in the same location as the bond.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  3. #3
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    Sometimes this guide helps.
    As ActionDave states, 250.30 has your basic requirements.

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    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    I love that graphic.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  5. #5
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    The only clamp the OP refers to that I can think is a kenny clamp. Never used one myself. Always mounted a little busbar.


    http://kennyclamp.com/
    "Electricity is really just organized lightning." George Carlin


    Derek

  6. #6
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    thanks guys

    thank you guys,

    Ok so what about where the gec enters the xfmr case? I have read that passing it through the bottom mesh is not compliant because it is not bonded where entering. The job I'm on now we have been using an mc connector and stripping the gec at that point where it enters but I know that an mc connector is not listed for that use.

    I also realize I should've posted this in 'grounding vs bonding'

  7. #7
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    Quote Originally Posted by hacim23 View Post
    I have read that passing it through the bottom mesh is not compliant because it is not bonded where entering.
    That is the issue that comes up. But the NEC does not actually say the bonding has to be done at the point the GEC enters people assume that part.



    Apparently some inspectors require the use of the 'Kenny clamp' to bring a GEC into an enclosure. In my opinion that is beyond what the NEC requires.

  8. #8
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    Quote Originally Posted by iwire View Post
    Apparently some inspectors require the use of the 'Kenny clamp' to bring a GEC into an enclosure. In my opinion that is beyond what the NEC requires.
    I agree, you would only need to bond it separately if you were using a metallic raceway. If you needed a listed fitting to enter the enclosure then you might need the Kenny clamp. I would ask if you were using PVC would you need a Kenny clamp or a bonding bushing?
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  9. #9
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    Quote Originally Posted by infinity View Post
    I agree, you would only need to bond it separately if you were using a metallic raceway.
    If I run say EMT directly into the transformer cabinet isn't the raceway already bonded to the GEC at XO?

  10. #10
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    Quote Originally Posted by iwire View Post
    If I run say EMT directly into the transformer cabinet isn't the raceway already bonded to the GEC at XO?
    Yes, same as using EMT to run a GEC into a service enclosure but it seems that many people (inspectors and electricians) believe that you would still need to bond the GEC directly to the EMT with a bonding bushing. I see no point in that for the reason that you've mentioned.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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