Circuit Load (Amps) = Appliance Wattage / Circuit Voltage But hold on—you can't max out the breaker! Electrical codes (like NEC) require breathing room. We follow the 80% rule : Safe Continuous Load = Circuit Breaker Rating × 0. 8 Example: Need a circuit for your 1,800W. Abstract: Understanding the loads connected to an electrical system is an essential consideration when designing or operating said system. Determining the size of the equipment required, including fault interrupting devices, bus bars, conductors, and similar, is not just a summation of connected. Free electrical load calculation tool for residential and commercial buildings. Calculate service entrance sizing, panel loads, demand factors, and ensure NEC Article 220 compliance.