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    NEC Voltage Drop Calculator (Free)

    What is the maximum voltage drop NEC allows?

    NEC 210.19(A) and 215.2(A) informational notes recommend a maximum 3% voltage drop on branch circuits and 5% combined on feeder + branch — they are recommendations, not mandates, but most AHJs enforce them.

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    Estimates and general guidance only. Verify against your local code and AHJ before any installation. Gas, electrical, and refrigerant work is hazardous to untrained users.

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