Branch Circuits & FeedersQuestion 26 of 120
What is the allowable ampacity of 4/0 AWG copper THWN in the 75 degrees C column?
a.195 amperes
b.205 amperes
c.260 amperes
d.230 amperes
Explanation
Table 310.16 lists 4/0 copper at 230 amperes in the 75 degrees C column. The 260-ampere figure is the 90 degrees C value and may be used only as a derating base, 195 amperes is the 60 degrees C value, and 205 amperes belongs to 3/0 copper at 90 degrees C rather than 4/0.
Law Reference: 2023 NEC Table 310.16Practice all 120 questions free — no signup required.
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