Calculate wire size for NEC compliance
This calculator helps you choose the correct wire size to keep voltage drop within safe limits according to NEC (National Electrical Code) standards.
What is voltage drop? When electricity travels through wire, some voltage is lost due to resistance. Too much drop can damage equipment and violate code.
NEC Standards: The NEC recommends keeping voltage drop under 3% for branch circuits and 5% maximum for combined feeder and branch circuits.
How to use: Enter your system voltage, the current (amps) the circuit will carry, the one-way distance the wire must travel, and select your wire material. The calculator will recommend the minimum wire gauge needed.