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Thread: Parallel ground wires

  1. #1
    Join Date
    Jul 2013
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    Arcata, CA
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    Parallel ground wires

    We have two 15hp air compressors, both fed from the same subpanel. Each has what I believe is an appropriate sized ground wire (I can't see the printing). There is also an A-B panel to control which one has priority.

    In the wiring to the A-B panel, there is also a (12 gauge) ground wire, creating a parallel path to the larger wire in the main compressor power feed. Is this OK? I wouldn't bring this up if I thought it was, but I am not sure.

    Thanks.

  2. #2
    Join Date
    Feb 2003
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    Bremerton, Washington
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    The EGC (the term ground is vague and not code language ) is not a current carrying conductor so no issues with parallel path. If you have metallic raceway that creates a parallel path.
    What you want is a path to the source to clear a line to case fault, based on your description an EGC sized based on 250.122 from each compressor.
    I would rather see the NEC use the term equipment bonding conductor, as that is what it does.
    Mostly we know what you mean when you say ground.
    Moderator-Washington State
    Ancora Imparo

  3. #3
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    Feb 2016
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    Illinois
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    How is the AB (sequencer) panel powered? This could make a difference.

  4. #4
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    Quote Originally Posted by retirede View Post
    How is the AB (sequencer) panel powered? This could make a difference.
    From the same subpanel as the compressors. They are all right there in the compressor shed.

  5. #5
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    There is nothing wrong with multiple EGC paths whether they be of the wire type or metallic raceways.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  6. #6
    Join Date
    Feb 2016
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    Illinois
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    Quote Originally Posted by Barbqranch View Post
    From the same subpanel as the compressors. They are all right there in the compressor shed.
    Sometimes they are powered from one of the compressors.

    The EGC you are questioning is fine, perhaps unnecessary.

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