Do I need to derate terminal ratings similar to conductor ratings if they are in ambient temperatures other than 30 deg C? For example if I have an AC disconnect with 75 deg C terminals mounted outdoors with a max ambient temp of 39 deg C and I land #6 THWN-2/THHN 90 deg C wire on that terminal do the 75 deg C terminal still have a 65 A rating (for #6 @ 75 deg C in table 310.15(B)(2)(b)) or do I need to apply the 0.88 derate to this terminal rating because it is in 39 deg C ambient temp?