A residential electrical system requires 20 AWG copper conductors for branch circuits. What is the maximum allowable fill for a 1-inch conduit, according to the 2026 NEC?

Texas Master exam practice question · Wiring Methods & Materials

A residential electrical system requires 20 AWG copper conductors for branch circuits. What is the maximum allowable fill for a 1-inch conduit, according to the 2026 NEC?

A50%
B60%
70%
D80%

Exam tip

Remember that conduit fill calculations are based on the size of the conduit and the number of conductors.

Why C is correct

The 2026 NEC Article 318.10(A) allows for a maximum fill of 70% for conductors in raceways. The 50% and 60% options are incorrect as they are not allowed by the code, and the 80% option exceeds the maximum fill.

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A residential electrical system requires 20 AWG copper conductors for branch circuits. What is the maximum allowable fill for a 1-inch conduit, according to the 2026 NEC?

A residential electrical system requires 20 AWG copper conductors for branch circuits. What is the maximum allowable fill for a 1-inch conduit, according to the 2026 NEC?

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