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Tuesday, February 22, 2022

Question:

Hello and thanks for this NEC forum.

If a  run of 4-inch EMT is installed for a feeder protected by a 400-ampere breaker, what is the minimum size equipment grounding conductor required for the circuit?

Henry Oates

A

Answer:

Hi Henry,

Based on the information in the question, by NEC minimum requirements, the EMT can serve as the required equipment grounding conductor, See Section 250.118(4). If a wire-type equipment grounding conductor is installed for this feeder, the minimum size required for the feeder would be 3 AWG copper, based on Section 250.122 and Table 250.122.

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