Born and raised in central FL. Recently moved to upstate SC. Taking classes in residential and commercial wiring. I am terribly confused by the wording differences between 110.14C1a2 and 110.14C1b2; "ampacity is determined based on" versus "ampacity does not exceed", respectively. Has that been discussed? Should that be a new thread? Obviously it is significant or they would have worded it the same way. Under 100 amps, 55 amp conductor is fine for 40 amp load. Over 100 amps 170 amp capable conductor is no good for a 150 amp load because it exceeds "the 75C ampacity" of the conductor? How does that make sense?