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Thread: GFP 230.95

  1. #1
    Join Date
    Aug 2011
    Location
    NH
    Posts
    243

    GFP 230.95

    A 1200A frame breaker with 600A trip unit is installed on a 480 VAC 3 phase standby generator that feeds plant distribution through a 3 pole / solid neutral ATS.

    My understanding is with the 600A trip unit, no GFP on the breaker is required (actual overcurrent device installed). If they need the GFP enabled then the 3 pole ATS could present a problem.

    Am I correct that no GFP required in this case?

  2. #2
    Join Date
    Feb 2003
    Location
    Illinois
    Posts
    23,652
    230.95 would not apply to conductors from a generator, 215.10 would apply. However 215.10 does refer back to 250.95 for the specific requirements of the GFP. Based on the wording in 230.95, I agree that GFP would not be required.
    230.95 ... The rating of the service disconnect shall be considered to be the rating of the largest fuse that can be installed or the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted.
    It would be my opinion that the rating of the trip unit is the rating of the "actual overcurrent device". That does seem to treat breakers differently than fuses as in many cases it is no more difficult to change the trip unit than it is to change a fuse.
    Don, Illinois
    Ego is the anesthesia that deadens the pain of stupidity. Dr. Rick Rigsby
    (All code citations are 2017 unless otherwise noted)

  3. #3
    Join Date
    Aug 2011
    Location
    NH
    Posts
    243
    [QUOTE=don_resqcapt19;1914852]230.95 would not apply to conductors from a generator, 215.10 would apply. However 215.10 does refer back to 250.95 for the specific requirements of the GFP. Based on the wording in 230.95, I agree that GFP would not be required.
    QUOTE]
    Thanks for the correction - I agree 215.10 is the correct reference - I looked at 230.95 because all the GFP sections seem to point back there.

    The difference in the requirements between fuses (largest fuse that can be installed) and breakers (actual overcurrent device installed) was the reason for my original question. It sounds like you interpreted the same way I interpret.

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