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Generator circuit breaker(s) mounting height

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    Generator circuit breaker(s) mounting height

    I have an installation where a 480V standby generator is equipped with four breakers. Three of these are for feeds to the emergency side of transfer switches and one is for a load bank. The circuit breakers are mounted on the machine, high off the ground (well over 6'-6", I don't know the exact height). The generator frame and breakers are inside an enclosure which is on top of a belly tank, the door of which must be opened to gain access to the breakers and generator control panel.

    The breakers are certainly not readily accessible as required in 240.24(A) -- currently there is no permanent method to reach the handles. Reading through 445, however, I do not see anything that indicates generator breakers need to be readily accessible. Currently people are using a roll away step ladder with hand rails when they need to gain access to the breakers or control panel.

    I am struggling to determine if this installation is code compliant. Is the height of the breakers a code violation? If it is, I do not know how we will be able to resolve the issue as there isn't much room in the area beneath the breakers. Thank you for any input.

    #2
    They are a part of the unit. If you are trying to use them for something that needs to have ready access you may need to add additional devices elsewhere to meet that requirement.
    I live for today, I'm just a day behind.

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      #3
      Originally posted by kwired View Post
      They are a part of the unit.
      Why is this significant? Does having the CBs as part of the generator remove the mounting height requirement?

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        #4
        Originally posted by AZElectrical View Post
        Why is this significant? Does having the CBs as part of the generator remove the mounting height requirement?
        The breaker in the unit is likely there for overcurrent protection of the unit. If you are supplying something that needs a readily accessible disconnecting means - you are going to have to install an additional disconnecting means to comply with that requirement.

        The unit is listed as is, removing the breaker in the unit compromises that. Now if instructions for the unit (which are part of it's listing) say you need certain access, then you may still have issues anyway.
        I live for today, I'm just a day behind.

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          #5
          Originally posted by AZElectrical View Post
          Why is this significant? Does having the CBs as part of the generator remove the mounting height requirement?
          Because the NEC does not apply like that to listed assemblies.

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            #6
            Originally posted by iwire View Post
            Because the NEC does not apply like that to listed assemblies.
            It's possible the unit was listed without the fuel tank under it. I see it a lot.
            Sometimes I don't know whether I'm the boxer or the bag.

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              #7
              Originally posted by iwire View Post
              Because the NEC does not apply like that to listed assemblies.
              I have spent the past day or so trying to find a section in the (2011) NEC that states something along these lines. Is this explicitly stated anywhere? I should note that I do believe what you've said, I just can't find it written anywhere.

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                #8
                Originally posted by AZElectrical View Post
                I have spent the past day or so trying to find a section in the (2011) NEC that states something along these lines. Is this explicitly stated anywhere? I should note that I do believe what you've said, I just can't find it written anywhere.
                Nothing in the NEC out right says NEC doesn't apply if an item is listed that I am aware of, but if you read through 110.3 it kind of says that. Informational note in there does sort of say that listing, labeling, and following product instructions is one way to determine if something is suitable for use.
                I live for today, I'm just a day behind.

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