I was told once that for figuring out cable ampacity, anytime you go above 1/0 that you have to use the 60 degree rating even if you have 90 degree cable because the connectors above that size are only rated for 60 degree's. Is this true and where can I find this? I have not been able to find temp ratings on lugs, probably right in front of my eyes and I can't see it.
Cable ampacity
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Re: Cable ampacity
You must choose you conductor rating based on the terminal temperature rating of the device to which you are connecting the conductor. Today new equipment comes with terminal ratings of 75C. Therfore regardless of the conductor size you would use the 75C column. This rule is listed in 110.14(C)1.3.
If you must derate the conductor as shown in table 310.15B2a or adjust the rating for temperature as shown in table 310.16 then you may use the 90C rating. However the resulting 90C ampacity may not be greater than that shown in the 75C column for the same size conductor.
You must choose you conductor rating based on the terminal temperature rating of the device to which you are connecting the conductor. Today new equipment comes with terminal ratings of 75C. Therfore regardless of the conductor size you would use the 75C column. This rule is listed in 110.14(C)1.3.
If you must derate the conductor as shown in table 310.15B2a or adjust the rating for temperature as shown in table 310.16 then you may use the 90C rating. However the resulting 90C ampacity may not be greater than that shown in the 75C column for the same size conductor.
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