Services & DistributionQuestion 94 of 521

Six current-carrying conductors are installed in a single raceway. The ampacity adjustment factor that must be applied to each conductor is:

a.80%
b.70%
c.50%
d.100%

Explanation

Per Table 310.15(C)(1), for 4 through 6 current-carrying conductors the adjustment factor is 80%. Seven through nine conductors use 70%, and 100% would apply only to three or fewer conductors, so those factors do not fit six conductors.

Law Reference: 2023 NEC §310.15

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