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Thread: Transformer/ Main panel

  1. #1
    Join Date
    Jun 2006
    Posts
    127

    Transformer/ Main panel

    Hello all

    I have a 45kva transformer that secondary wired terminate in a 150amp main panel breaker. In that panel the neutral and grounds are seperated. Shouldn't they be bonded together after a SDS? I say yes but my foreman disagrees...

  2. #2
    Join Date
    Oct 2006
    Location
    Baltimore, MD
    Posts
    3,159
    Yes. Bonded at the transformer or first disconnect. 250.30(A)(1)
    John from Baltimore
    "One Day at a Time"
    Responses based on the 2008 NEC

    If you can stay calm, while all around you is chaos...then you probably haven't completely understood the seriousness of the situation

  3. #3
    Join Date
    Jul 2005
    Location
    Tennessee
    Posts
    12,223

    transformer grounding


  4. #4
    Join Date
    Feb 2003
    Location
    Massachusetts
    Posts
    48,245
    As John pointed out it's either bonded at the transformer or the first disconnecting means, or in some cases it can be done at both.

    I always bond at the transformer, I think it keeps the panel cleaner looking.

  5. #5
    Join Date
    Jan 2005
    Posts
    907
    if the grounds and neutrals are separated at the 150 amp panel the bonding jumper would have to be at the transformer

  6. #6
    Join Date
    Mar 2006
    Location
    Tampa Florida
    Posts
    8,009
    If you dont how will it clear a fault ?

  7. #7
    Join Date
    Feb 2006
    Location
    Pa.
    Posts
    2,010
    Quote Originally Posted by Jim W in Tampa
    If you dont how will it clear a fault ?
    You need to open the transformer or panel and look for the jumper.The GEC should also be installed where the jumper is made.
    Rick

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