Tools you might need next
Size circuit breaker from wire gauge and load type. Match overcurrent protection to conductor ampacity per NEC 240.4 for residential circuits.
Calculate total electrical load for residential service sizing. Sum appliance watts and apply demand factors for panel and service entrance capacity.
Select AWG wire size from ampacity and circuit load. Calculate conductor size for copper and aluminum per NEC ampacity tables with temperature rating.
15A × 120V = 1,800W; 20A × 120V = 2,400W maximum recommended load on general circuits.
Max Load = Breaker Amps × Voltage × 0.80 (continuous)Load calculations count 180 VA minimum per duplex outlet for service load calc — actual plug load may differ.
General load allowance: 180 VA per receptacle (NEC 220.14(I))Diversity — not all outlets draw max simultaneously. Kitchen counters require dedicated 20A small appliance circuits.
Operating Load = Σ Appliance Watts actually used simultaneouslyUpdated: July 2026
PC, monitors, printer on 15A circuit: 1,400W < 1,800W limit. Avoid space heater on same circuit.
NEC requires minimum two 20A small appliance circuits for kitchen countertop. No lighting on these circuits.
Table saw 1,800W plus shop vac exceeds 15A circuit — run dedicated 20A for tools.
Estimate total load on general-purpose receptacle circuits to avoid overload. Enter number of outlets, expected connected wattage, and circuit breaker rating to verify load stays within NEC limits and plan circuit layout.