Services & DistributionQuestion 18 of 521
A 4/0 AWG copper THHN conductor (90 C, base 260 A) is in an ambient of 45 C. Using the 0.87 correction factor, what is the corrected ampacity?
a.226 A
b.247 A
c.195 A
d.260 A
Explanation
260 A x 0.87 = 226 A after applying the 41-45 C temperature-correction factor from Table 310.15(B) to the 90 C column. 260 A ignores correction, and the other values use wrong factors.
Law Reference: 2023 NEC §310.15(B)Practice all 521 questions free — no signup required.
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