I have a question about Table 310-15(b)(2)(a).Correct me if I'm wrong folks! If I run 4 #14AWG THHN conductors (2 hot 2 neutral) in a 1/2 emt from a panel to say a bedroom for 2 circuits 30 feet away, these conductors SHALL be derated by 20%. Which means that each conductor now has the ampacity of 16amps correct? If I ran 10 #14 AWG THHN (to feed 2 bedrooms with lighting and several receptacles)I would derate by 50%, which each one is now rated at 10 amps. What is the correct overcurrent protection for both? First example 15 amp breaker? Second example 10 amp? Keeping in mind Art 240-3(b)etc.
Thanks in advance to all. Gunny
Thanks in advance to all. Gunny