Temperature ratings of terminals

[jcleavit]

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.

 

[jumper]

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.

 

[don_resqcapt19]

I haven't seen a termination marked for 60°C in years, but most tests will want to see what matches 110.14.

 

[infinity]

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.

 

[jumper]

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.php?id=RTDV.GuideInfo

I looked at a few flush mounts and the strap/yoke was stamped 75C.