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Thread: panel board as an EGC

  1. #31
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    Quote Originally Posted by JJspark View Post
    I talked to the inspector today about this. He said it is not UL listed to be an EGC.
    State Inspector?
    CircuitRyder --- Unfortunately not all good ideas are code enforceable.

  2. #32
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    Quote Originally Posted by JJspark View Post
    I talked to the inspector today about this. He said it is not UL listed to be an EGC.
    As I ponder this further, the more absurd it is. Let's try another example. Let's say you have sub panel fed with a metallic raceway that qualifies as an EGC and you have no wire type EGC in the feeder. Then you add branch circuits that have a wire type EGC so you add a factory ground bar kit to land them on. It should be obvious that whether you have 1 or 4 ground bars with a jumper between them the enclosure will still have to carry the short circuit current back to the feeder conduit. I would ask this inspector would he require a bonding jumper if you only had 1 ground bar and if so where would you connect each end?

  3. #33
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    Quote Originally Posted by JJspark View Post
    I talked to the inspector today about this. He said it is not UL listed to be an EGC.
    Well he's incorrect, now is up to you to decide if you want to fight him on it by going over his head or just add the jumpers. What size jumpers did he say that you're "required" to use?
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  4. #34
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    Quote Originally Posted by JJspark View Post
    I talked to the inspector today about this. He said it is not UL listed to be an EGC.
    He might be correct, only because it was never tested for that specific purpose, but no real need to if NEC recognizes it as being suitable to use as part of the EGC path.

  5. #35
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    Quote Originally Posted by petersonra View Post
    where does it say in the code that metal boxes have to be listed?
    250.118.

    It doesn't have to be listed to use it as a box, but it has to be listed if you want to use it as an EGC. That is, if it's not one of the other items identified in that section.

  6. #36
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    There's a fundamental conflict between the definition of EGC, 250.118, and common practice:

    (2017) Grounding Conductor, Equipment The conductive path(s) that provides a ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both.

    (2017) 250.118 Types of Equipment Grounding Conductors. The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more of a combination of the following:

    Now "metallic equipment enclosures" clearly "enclose circuit conductors" yet are not listed in 250.118. But common practice is to rely on metallic equipment enclosures as a component of the "ground-fault current path". Hence the conflict.

    This could easily be resolved by adding "metallic equipment enclosures" to the list in 250.118. Right now everyone behaves as if that were the case.

    Cheers, Wayne

  7. #37
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    Quote Originally Posted by JJspark View Post
    I talked to the inspector today about this. He said it is not UL listed to be an EGC.
    If the enclosure is not UL listed to be EGC then essentially what he requires is all of the metallic conduits to have a grounding bushings as they enter the enclosure.
    Edward
    Education is a progressive discovery of our ignorance.


  8. #38
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    250.96 (A) specifically mentions enclosures, which allows the practice .


    I think this is merely a case of that inspector once read that the building steel is not to be used as a bonding path. A panel board is not '' building steel'', but of course many inspectors once countered with that will begin with the '' we interpret this to mean the panel boards are what this is referring to.....
    85deg. an Sunny today.

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