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Thread: Double Taps

  1. #1
    Roni Litmanovic's Avatar
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    Default Double Taps

    Assuming the breaker does not specify adequacy, are double tapps allowed on a 15 or 20amp single pole breaker? I noted a double tap in a brand new condo and the supervising engineer argued it was not a problem as long as the conductors correspond to the same circuit. Can some one help me with this and I would love to know what the NEC rule says.

    Thanks,

    Roni

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  2. #2
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    Default Re: Double Taps

    Two wires may only be terminated on a breaker that is listed for use with more than 1 conductor and within the sizes shown on the breaker. UL does the listing and the Code article would be that equipment must be used as listed.

    What was the brand of the breaker? Square D, both Homeline and QO, and some Cutler-Hammer CH are listed for multiple conductors. This is only on the smaller breaker sizes like 15, 20 and 30s.


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    Default Re: Double Taps

    The other Jim is right. Some breakers allow it. On another note, how could the conductors not correspond to the same circuit if they are on the same breaker?

    Jim Robinson
    New Mexico, USA

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    Default Re: Double Taps

    Quote Originally Posted by Roni Litmanovic View Post
    and I would love to know what the NEC rule says.
    Quote Originally Posted by Jim Port View Post
    What was the brand of the breaker? Square D, both Homeline and QO, and some Cutler-Hammer CH are listed for multiple conductors. This is only on the smaller breaker sizes like 15, 20 and 30s.
    .


    You asked, so here is what the NEC says on it: (underlining is mine)
    - 110.14 Electrical Connections.
    - - (A) Terminals. Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors.
    - - -Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

    Basically, with Square D, the terminals which are rated for two conductors is a pressure plate which has two raised arch areas, one on each side of the pressure plate, under which the conductor goes. Note that you are NOT allowed to place two conductors on one side, if two conductors are installed, one must be at each "terminal receptor" location, i.e., one conductor under one raised arch side of the pressure plate.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Double Taps

    Good replies! The solution is to take the two conductors and wire nut them to a piece of conductor 12 inches long. Then terminate the single conductor to the breaker..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: Double Taps

    Quote Originally Posted by Roland Miller View Post
    Good replies! The solution is to take the two conductors and wire nut them to a piece of conductor 12 inches long. Then terminate the single conductor to the breaker..

    Not always true... it's a single circuit then and you can overload the pigtail.


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    Default Re: Double Taps

    Quote Originally Posted by Matt Fellman View Post
    Not always true... it's a single circuit then and you can overload the pigtail.
    Nope, always true (cannot think of when it would not be true, provided that the spliced on conductor rating matches the breaker rating).

    It does not matter if you have two 20 amp circuits (#12 AWG) and splice them together to a third #12 AWG to the breaker - the breaker will still protect that single #12 AWG at it 20 amp rating.

    You will not "overload the pigtail", you may, however, now overload the breaker ... unless you are correcting a multiple tap - which means those circuits were already on that breaker, you are just correcting an incorrect termination problem.

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    Default Re: Double Taps

    Say you have two circuits each loaded to 90% of what a given conductor is rated to carry, each terminating at the said breaker. Once you combine them and they 'share' the last 12" isn't that overloading that 12" section?


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    Default Re: Double Taps

    Matt--you are correct. My solution is based on the assumption that the breaker was not overloaded with the two conductors terminated on it.

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: Double Taps

    Quote Originally Posted by Matt Fellman View Post
    Say you have two circuits each loaded to 90% of what a given conductor is rated to carry, each terminating at the said breaker. Once you combine them and they 'share' the last 12" isn't that overloading that 12" section?
    Not the same thing as is being discussed.

    What is being discussed is that there are two circuits multiple tapped to ONE breaker, meaning that you could not have BOTH of those circuits at 90%, because the breaker would trip.

    So, given what we are talking about, the way you correct a multiple tap is to remove both conductors, connect those two conductors to a new third conductor, then terminate the new third conductor to the breaker.

    NOTHING is overloaded, not that last 12", not the breaker, NOTHING.

    What you are bringing into the mix is (I presume) taking two circuits from TWO breakers, connecting them together with a new conductor, then terminating that new conductor to a breaker.

    STILL NOT OVERLOADING on that new conductor as the breaker will trip and protect that new conductor.

    Yes, though, those TWO previously independent circuits will OVERLOAD THE BREAKER if each were trying to pull 90% load of the breaker rating.

    Jerry Peck, Construction / Litigation Consultant
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  11. #11
    Inspector 3500's Avatar
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    Default Re: Double Taps

    Quote Originally Posted by Roland Miller View Post
    Good replies! The solution is to take the two conductors and wire nut them to a piece of conductor 12 inches long. Then terminate the single conductor to the breaker..
    The panel would need to be listed as having a space for splices and the splice would need to be located in that area/section of the panel.


  12. #12
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    Default Re: Double Taps

    UL doesn't specifically allow or prohibit splicing in panels. It then becomes a call for the inspector or AHJ (oh no not that!!).

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  13. #13
    Jeff Remas's Avatar
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    Default Re: Double Taps

    Splicing in the main panel is allowed by the NEC providing that there is enough space for 'box fill'. If we did not approve it, it would be difficult to replace main panels. Cutler Hammer has a nice panel that comes with insulated terminal strips for wires that are too short to make it to the breaker in the new panel. It eliminated wire nuts in the panel and looks more professional.


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    Default Re: Double Taps

    Quote Originally Posted by Inspector 3500 View Post
    The panel would need to be listed as having a space for splices and the splice would need to be located in that area/section of the panel.
    That space is already provided for in the panel - *as long as* those splices terminate within the panel. Otherwise (it those wires do not terminate in the panel) the panel now becomes a raceway and that use is not allowed.

    Plus, if you would, please click on the 'Contact Us' link at the bottom of the page and ask Brian to change your username to your real name, we use our real names here as that allows us to 'get to know each other better'. Thanks.

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