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Thread: 2-13 MWBC for Pump/Alarm

  1. #1
    Join Date
    Dec 2004
    Location
    Fort Collins, CO NEC: 2014
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    15,380

    2-13 MWBC for Pump/Alarm

    Add new exception to 210.4(B):
    Exception: Where a multiwire branch circuit with line to neutral loads must be used at a separate structure in order to comply with 225.30, and an alarm circuit is required for its safe operation is part of this multiwire branch circuit.
    1.) Comment on Proposal No.: 2-13
    2.) Recommendation: Accept the proposal in part as follows:
    Exception: Simultaneous disconnection of ungrounded conductors of a dedicated multiwire branch circuit supplying a combination pump controller and alarm may be omitted if all supply conductors are contained within the same wiring method at the controller. A warning label shall be placed on the panelboard that clearly states that both circuits supplying the pump and alarm require disconnection prior to maintenance or repair.
    3.) Substantiation: A pump controller featuring a 120V pump on the first line and a 120V alarm on the second line of a multiwire branch circuit with no stops in between should not pose a surprise to qualified personnel if all conductors are present and terminate within the same enclosure. A pump that trips the OCPD and inadvertently also trips the supply to the alarm defeats the entire purpose of having the alarm. The label was added as an afterthought to sweeten the deal.

  2. #2
    Join Date
    Dec 2006
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    Chapel Hill, NC
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    I had made a proposal to allow a mwbc for this purpose and it was rejected. I also proposed that 2 circuits be allowed to run the the tank - one for the pump and one for the alarm-- citing 225.30. They said that 225.30 was never meant to disallow two circuits to a specialty equipment.

    Well, it does not give an exception so why not have one. I am not sure why that was denied.

  3. #3
    Join Date
    Dec 2004
    Location
    Fort Collins, CO NEC: 2014
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    Quote Originally Posted by Dennis Alwon View Post
    I had made a proposal to allow a mwbc for this purpose and it was rejected.
    Indeed - it's your proposal that I am commenting on.

    I also proposed that 2 circuits be allowed to run the the tank - one for the pump and one for the alarm-- citing 225.30. They said that 225.30 was never meant to disallow two circuits to a specialty equipment.

    Well, it does not give an exception so why not have one. I am not sure why that was denied.
    225.30(D) could be used to get that done, but it would involve an argument with the AHJ to make it so.

  4. #4
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    25,752
    I thought they were saying 2 circuits were okay as 225.30 does not apply to this specialized equipment. Where they got that from I am not sure.

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