FeederCalc
NEC Feeder Circuit Calculator

Important Disclaimer

Disclaimer: This calculator provides estimates based on NEC standards and simplified data. Assumes 75°C conductor terminals, standard ambient temperature (30°C), and no more than 3 current-carrying conductors per raceway for base ampacity before paralleling. Does not account for all derating factors (e.g., high ambient temp, >3 CCC in one conduit after paralleling adjustments), continuous load factors (125% unless otherwise noted), or specific installation conditions. Voltage drop is an estimate based on approximate impedance values (NEC Ch9, T9 @ 0.85 PF) and calculated at 80% of the input amperage per set unless noted otherwise. Parallel run calculations require verification that all NEC paralleling requirements (e.g., same length, material, size, insulation, termination) are met. Always consult the current National Electrical Code, local regulations, and manufacturer specifications. Verify all calculations with a qualified professional before installation.