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Thread: Temperature ratings of terminals

  1. #1
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    Temperature ratings of terminals

    I am an instructor and I had a question from one of the teachers that I work with. I have been teaching that you always assume, unless the questions specify 75 degrees C terminals, that any calculation done that will terminate on a piece of equipment to be 60 degrees C if you are 100A or less. He was told by somebody else that because of the "real world" aspect of almost all, if not all, new equipment being rated 75 C that even testing situations we should assume the terminals are 75 C rated. I just need to know what the journeyman test wants you to assume here so I don't lead my guys wrong.

  2. #2
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    I agree with you. 110.14(C)(1) backs your assumption.

    Note that it applies not only to 100A or less but terminations for #14-#1 also.
    "Electricity is really just organized lightning." George Carlin


    Derek

  3. #3
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    I haven't seen a termination marked for 60°C in years, but most tests will want to see what matches 110.14.
    Don, Illinois
    Ego is the anesthesia that deadens the pain of stupidity. Dr. Rick Rigsby
    (All code citations are 2017 unless otherwise noted)

  4. #4
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    What about receptacles or generator inlet boxes? I installed a Generac 50 inlet box and the device and it's literature had no terminal temperature specifications which led me to believe that it was by default 60° C. When I contacted Generac they confirmed my suspicion that the device had only 60° C terminals which complicated the installation because I had run 8/3 MC cable with a 50 amp CB.

    I also wonder if a 50 amp range receptacle has 60° C or 75° C terminals, or any receptacle that accepted #1 AWG or less conductors for that matter.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  5. #5
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    Quote Originally Posted by infinity View Post
    What about receptacles

    I also wonder if a 50 amp range receptacle has 60° C or 75° C terminals, or any receptacle that accepted #1 AWG or less conductors for that matter.
    From UL white book receptacles:

    Unless stated otherwise in the individual product categories, the termination provisions of all other devices are based upon the use of 60°C insulated conductors in circuits rated 100 A or less, and the use of 75°C insulated conductors in circuits rated more than 100 A, as specified in Table 310.15(B)(16) of the NEC.
    http://productspec.ul.com/document.p...RTDV.GuideInfo

    I looked at a few flush mounts and the strap/yoke was stamped 75C.
    "Electricity is really just organized lightning." George Carlin


    Derek

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