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Thread: Can multiple single barrel lugs land on a single terminal

  1. #1
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    Can multiple single barrel lugs land on a single terminal

    This question is very closely related to a now closed thread titled: Can multiple single lugs on a secondary side of a transformer, be bolted together? At the bottom of the thread a member posted a surface area question that was not answered.

    The application here is a parallel set of 350s with single barrel lugs that land on the same side of a terminal; The lug that is in contact with the terminal would receive twice the ampacity it was rated for because of the 2nd lug that is on top of it.Name:  image002.jpg
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    Is this a code violation? I'm having difficulty understanding whether the bottom lug would be able to carry the extra current. Thank you for the help.

  2. #2
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    Quote Originally Posted by wtrbfflo View Post
    This question is very closely related to a now closed thread titled: Can multiple single lugs on a secondary side of a transformer, be bolted together? At the bottom of the thread a member posted a surface area question that was not answered.

    The application here is a parallel set of 350s with single barrel lugs that land on the same side of a terminal; The lug that is in contact with the terminal would receive twice the ampacity it was rated for because of the 2nd lug that is on top of it.Name:  image002.jpg
Views: 292
Size:  18.4 KB

    Is this a code violation? I'm having difficulty understanding whether the bottom lug would be able to carry the extra current. Thank you for the help.
    The current to the top lug goes along the long side (tongue) of the lug. There is plenty of metal there. Lugs like this are stackable.

    Also look at the amount of metal where the lug tapers down from the tongue to the ferrule compared to the surface area of where the two tongues meet.

    Did someone put a piece of copper foil in there?
    Bob

  3. #3
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    I agree. If you look at the catalogue of these type of lugs, they specifically show them being stacked.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  4. #4
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    I agree too lugs are stackable and often come from the manufacturer just like in the photo. They even make offset lugs to stack several of them together.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  5. #5
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    I was taught in the US Navy's Crimping School to install crimp lugs exactly as pictured in the OP.

  6. #6
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    From the UL Guide Information for "wire connectors and soldering lugs (ZMVV)".
    Stacking of connectors (multiple connectors assembled using a single bolt, nut and washers) may be permitted where mechanical interference is reduced or eliminated with the use of offset tangs, stacking adapters, and the like. The surface contact area of the mounting tang should make complete contact with the mounting surface or the previously stacked connector tang.
    Don, Illinois
    Ego is the anesthesia that deadens the pain of stupidity. Dr. Rick Rigsby
    (All code citations are 2017 unless otherwise noted)

  7. #7
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    Thanks all for the great responses! Bob - I believe that copper foil was a line drawn in the picture. Either way, it was a mock-up produced by the sub.

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