IB
Institute of Builders

Electrical Sizing

Strict adherence to the National Electrical Code (NEC/NFPA 70) is non-negotiable. Overloading circuits causes fires; under-sizing wire causes voltage drop.

Ohm's Law / Watt's Law Calculator

The foundation of all electrical circuit planning. Solve for Amperage to size your breakers properly.

Current Draw (Amps)
Warning: Continuous loads exceed 80% rule for a 20A circuit. Upsize required.