Branch Circuits & FeedersQuestion 12 of 120
What is the allowable ampacity of 8 AWG copper Type NM cable?
a.40 amperes
b.55 amperes
c.50 amperes
d.45 amperes
Explanation
The ampacity of Type NM cable must be taken from the 60 degrees C column of Table 310.16, where 8 AWG copper is 40 A, even though the conductors inside carry a 90 degrees C rating. The 50 A and 55 A choices come from the 75 degrees C and 90 degrees C columns, which may be used only as a starting point for derating, not as the final NM cable ampacity.
Law Reference: 2023 NEC §334.80Practice all 120 questions free — no signup required.
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