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    malu13's Avatar
    malu13 Posts: 12, Reputation: 1
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    #1

    Apr 19, 2009, 03:21 PM
    Factory installed jumper inside 3 Phase disconnect
    I have a 3 phase 30 amp disconnect switch that was sent out to a job, it is being used as
    A disconnecting means for a fujitsu mini split air conditioning system which is a 1 phase 208 volt system. In the disconnect there is a # 10 jumper between the load side of B phase to the line side of A Phase. Can anybody tell me why the jumper is there?

    Thanks
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
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    #2

    Apr 19, 2009, 03:33 PM
    Maybe to power a control circuit with a smaller fuse? Who know?

    Either way it is hack work.
    malu13's Avatar
    malu13 Posts: 12, Reputation: 1
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    #3

    Apr 19, 2009, 03:44 PM

    Maybe but why wouldn't they just jumper on the line side?
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
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    #4

    Apr 19, 2009, 05:34 PM
    Like I said, maybe they wanted the whole thing protected by the two single phase fuses and needed a smaller fuse for the control circuit.
    malu13's Avatar
    malu13 Posts: 12, Reputation: 1
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    #5

    Apr 19, 2009, 09:52 PM

    Yea,
    I see what you are saying, will check submittals tomorrow.
    Thanks for the insight,
    ohb0b's Avatar
    ohb0b Posts: 215, Reputation: 14
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    #6

    Apr 19, 2009, 11:11 PM
    Is this an un-fused disconnect? Are you sure it's a factory jumper? Was the disconnect supplied by the OEM, or did it come from the supply house?

    Sounds to me like someone wanted a convenience receptacle that was not switched by the disconnect, but didn't want to run a separate 15 amp line. (I've seen HVAC guys do stuff like this)

    Whatever the reason, it is a code violation.
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
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    #7

    Apr 20, 2009, 04:19 AM
    Quote Originally Posted by ohb0b View Post

    Whatever the reason, it is a code violation.
    How's that?

    Hack work? Yes.
    Violation??
    ohb0b's Avatar
    ohb0b Posts: 215, Reputation: 14
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    #8

    Apr 20, 2009, 09:45 AM
    Quote Originally Posted by stanfortyman View Post
    How's that?

    Hack work? Yes.
    Violation? ??

    There's a couple. If the jumper were installed to attempt compliance with 210.63 (Convenience receptacle powered from line side of line side of HVAC disconnect) it was probably a 15 or 20 amp receptacle. If the branch circuit was rated over 20 amps, this would be a violation of 210.21.

    Jumpering a switch is a violation of 404.15(B):

    Where in the off, position, a switching device marked OFF position shall completely disconnect all ungrounded conductors to the load it controls.

    Even if its not an NEC code violation, you can bet it will be a life safety code violation.

    Hack work... I agree!
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