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Thread: MWBC Question Again

  1. #51
    Join Date
    Apr 2018
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    Philadelphia
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    When in the world will a neutral have full voltage on it?we do know what a neutral does right? It carries minimal potential yes not saying to go lick the neutral but ive never come accross a neutral with 120v coming back if u have then your doing something way wrong


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  2. #52
    Join Date
    Jun 2013
    Location
    Massachusetts
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    72
    Quote Originally Posted by ActionDave View Post
    I think being forced to shut off three circuits instead of one makes it more likely someone will choose to work hot.

    I also think MWBC will die off in my lifetime. They will either be made illegal or they will be not allowed by job specs.

    I rarely see MWBC being used now. I know a while back they were used a lot especially for lighting circuits.

  3. #53
    Join Date
    Dec 2007
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    NE Nebraska
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    Quote Originally Posted by AntTnson View Post
    When in the world will a neutral have full voltage on it?we do know what a neutral does right? It carries minimal potential yes not saying to go lick the neutral but ive never come accross a neutral with 120v coming back if u have then your doing something way wrong


    Sent from my iPhone using Tapatalk
    In a two wire circuit it carries every bit of current the ungrounded conductor does. Disconnect it under load and touch it and you will be subject to full 120 or 277 volts of the supply circuit.

    In a multiwire circuit it is carrying unbalance current from the associated ungrounded conductors. You still don't want to disconnect it while loaded and touch it, how much voltage it will have to ground depends on how balanced the loads are.
    I live for today, I'm just a day behind.

  4. #54
    Join Date
    May 2011
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    4,639
    I've had a few bad experiences of disconnecting neutrals and finding they were live. More often from unintentional MWBCs, a.k.a. bad wiring, than from an intentional MWBC, but I've seen both and it amounts to much the same thing. Point being, yes, this is a real thing.

    I just wish people would mark and group MWBCs, or only use them with cable. I don't need handle ties if that's done.

  5. #55
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    Dec 2007
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    Quote Originally Posted by jaggedben View Post
    I've had a few bad experiences of disconnecting neutrals and finding they were live. More often from unintentional MWBCs, a.k.a. bad wiring, than from an intentional MWBC, but I've seen both and it amounts to much the same thing. Point being, yes, this is a real thing.

    I just wish people would mark and group MWBCs, or only use them with cable. I don't need handle ties if that's done.
    Which has been a rule for a while now, unless you are still on what 2005 or earlier NEC?
    I live for today, I'm just a day behind.

  6. #56
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    May 2011
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    Quote Originally Posted by kwired View Post
    Which has been a rule for a while now, unless you are still on what 2005 or earlier NEC?
    I know it's a rule. My complaint is people not following it. And I'm just saying it's a much more important rule than the handle-tie rule. For one thing, if there's multiple MWBCs in a single raceway, handle-ties don't tell you which neutral belongs to which hots.

  7. #57
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    Dec 2007
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    NE Nebraska
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    Quote Originally Posted by jaggedben View Post
    I know it's a rule. My complaint is people not following it. And I'm just saying it's a much more important rule than the handle-tie rule. For one thing, if there's multiple MWBCs in a single raceway, handle-ties don't tell you which neutral belongs to which hots.
    Apparently your inspectors aren't enforcing it either, or just aren't paying close enough attention to catch it if they do know better.
    I live for today, I'm just a day behind.

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