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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

  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

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    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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