how do you derate
according to annex c table c1 you can have 9 thhn 12's in a 1/2 and 16 thhn 12's in a 3/4 but do you have to derate cause of more than 3 current carring conductors on 310.15(B)(2)(a)
My question is when all the derating is done how many 12's and 10's can you put in 1/2 and 3/4 EMT