A commercial warehouse has a 100A, 480V branch circuit. What is the minimum allowable fill ratio for this circuit in a raceway, according to the 2026 NEC?

Texas Master exam practice question · Branch Circuit Conductors

A commercial warehouse has a 100A, 480V branch circuit. What is the minimum allowable fill ratio for this circuit in a raceway, according to the 2026 NEC?

A60%
B70%
80%
D90%

Exam tip

Be aware of the specific fill ratio requirements for different types of raceways and conductor sizes.

Why C is correct

According to 2026 NEC 318.17(A), the minimum allowable fill ratio for a 100A, 480V branch circuit in a raceway is 80%. The other options do not meet the NEC requirements.

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A commercial warehouse has a 100A, 480V branch circuit. What is the minimum allowable fill ratio for this circuit in a raceway, according to the 2026 NEC?

A commercial warehouse has a 100A, 480V branch circuit. What is the minimum allowable fill ratio for this circuit in a raceway, according to the 2026 NEC?

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