Where Type NM cable is run at angles with joists in unfinished basements and crawl spaces, it is permissible to secure cables not smaller than _____ conductors directly to the lower edges of the joist.
a) two 6 AWG
b) three 8 AWG
c) three 10 AWG
d) a or b
See answer and applicable Code reference
The correct answer is: d) a or b
The installation requirements for nonmetallic-sheathed cable (Types NM, NMC and NMS) can be found in Article