NEC Code Forum
I am using 90C rated wire (THWN-2) and I have source and destination enclosures with terminals rated for only 75C.
There are 4 current-carrying wires in my conduit between enclosures. Per NEC Table 310.15 (B)(3)(a), this gives a "number of wires derate" of 0.8.
My system is indoors, so there...