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Thread: panel board as an EGC

  1. #11
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    Quote Originally Posted by electrofelon View Post
    But how do you respond to the argument that a box or cabinet is not listed in 250.118? One could use bonding bushings and jumpers to bond around the box.
    If the cabinet is not listed then we can not use the conduit without the physical EGC.
    Edward
    Education is a progressive discovery of our ignorance.


  2. #12
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    Quote Originally Posted by edward View Post
    If the cabinet is not listed then we can not use the conduit without the physical EGC.
    Just to be clear, by "listed" you mean listed in 250.118, not as in UL listed right? I am inclined to agree with you, however this goes against what is clearly universally accepted practice. Think of 1900 boxes with emt and no wire EGC......
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  3. #13
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    Quote Originally Posted by electrofelon View Post
    Just to be clear, by "listed" you mean listed in 250.118, not as in UL listed right? I am inclined to agree with you, however this goes against what is clearly universally accepted practice. Think of 1900 boxes with emt and no wire EGC......

    Yes I meant listed as in 250.118.

    I don't understand the red section.

    OP, call the inspector tomorrow and ask for a code reference that you have violated.
    Edward
    Education is a progressive discovery of our ignorance.


  4. #14
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    Quote Originally Posted by edward View Post
    If the cabinet is not listed then we can not use the conduit without the physical EGC.
    We bond the cabinet, like all other metal parts, with metal conduit or we can use something like NM cable and its wire egc to bond the cabinet.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  5. #15
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    Quote Originally Posted by ActionDave View Post
    We bond the cabinet, like all other metal parts, with metal conduit or we can use something like NM cable and its wire egc to bond the cabinet.
    but I think there can be a difference in bonding a cabinet or box, and using a cabinet or box as an EGC (I am debating whether to hit submit reply or ponder that statement some more )

    I don't understand the red section.
    Consider an emt conduit run with no wire EGC, and some 4 square "pull boxes" in the run. The 4 sq box is the EGC for that part of the branch circuit or feeder.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  6. #16
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    Quote Originally Posted by electrofelon View Post
    but I think there can be a difference in bonding a cabinet or box, and using a cabinet or box as an EGC (I am debating whether to hit submit reply or ponder that statement some more )



    Consider an emt conduit run with no wire EGC, and some 4 square "pull boxes" in the run. The 4 sq box is the EGC for that part of the branch circuit or feeder.
    Yep. Like I said there is nothing in the code that says we can use any enclosure or box as an egc, we just do. In the 4 square box example the box is a "splice" for UL listed connectors and the NEC listed egc and everybody accepts that, cabinets with two egc busses mounted in it can be a little too freaky for some of the up tight crowd.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  7. #17
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    You do not need a wire type jumper from EGC bar to EGC bar. When you purchase the listed EGC bar it comes with two screws to connect it to the enclosure that's all that's required. You do not even need to remove any paint the deign of the screws does that for you.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  8. #18
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    In the OP's case, in my opinion, it depends whether the enclosure is listed by an NRTL. It probably is, but it is questionable whether the 4 separate terminal bars installed are following the listing instructions. If I didn't know the answer to that, I would probably connect them bonding jumpers just as a matter of good practice.

  9. #19
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    Quote Originally Posted by infinity View Post
    You do not need a wire type jumper from EGC bar to EGC bar. When you purchase the listed EGC bar it comes with two screws to connect it to the enclosure that's all that's required. You do not even need to remove any paint the deign of the screws does that for you.
    the screws bond the bar to the box. nothing says that makes the box a legal EGC.

    I am inclined to agree that it is just something that is done but actually not allowed by the code.

    However, for EMT and other metal conduit, the code allows the conduit or EMT to be an EGC. I think you can make a good argument that the UL listing effectively makes the box part of the EGC since the box is part of the conduit/EMT system.

    IMO, as for using an enclosure as an EGC in general, such as the situation the OP mentioned, you don't really have any good argument other than it is a common practice.
    Bob

  10. #20
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    Quote Originally Posted by petersonra View Post
    the screws bond the bar to the box. nothing says that makes the box a legal EGC.

    I am inclined to agree that it is just something that is done but actually not allowed by the code.

    However, for EMT and other metal conduit, the code allows the conduit or EMT to be an EGC. I think you can make a good argument that the UL listing effectively makes the box part of the EGC since the box is part of the conduit/EMT system.

    IMO, as for using an enclosure as an EGC in general, such as the situation the OP mentioned, you don't really have any good argument other than it is a common practice.
    So you cannot connect an EGC to a metal cabinet or enclosure? Same thing to me.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

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