Services & DistributionQuestion 19 of 521
Six current-carrying conductors are installed in a single raceway. What adjustment factor applies to their ampacity?
a.70%
b.50%
c.80%
d.100%
Explanation
Table 310.15(C)(1) applies an 80% adjustment factor for 4 to 6 current-carrying conductors. 70% is for 7-9, 50% is for 10-20, and no adjustment (100%) applies only to 3 or fewer.
Law Reference: 2023 NEC §310.15(C)(1)Practice all 521 questions free — no signup required.
Related questions on this topic
- What is the 75 C ampacity of a 4/0 AWG copper conductor per Table 310.16?
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- How many current-carrying conductors can be in a raceway before an adjustment (fill derating) factor must be applied?
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