buncha/engineering/loadcalc

Circuit Load Calculator

Loads on this circuit3 items · 120V

Watts

Volts

Continuous?

Amps

5.83 A

Watts

Volts

Continuous?

Amps

12.50 A

Watts

Volts

Continuous?

Amps

10.00 A

Recommended

Breaker

30 A

Copper wire

10 AWG

30 A at 75°C

Non-continuous(× 1.0)

28.3 A

Continuous(× 1.25)

0.0 A

Demand(sum)

28.3 A

Total power(raw)

3,400 W

Branch circuit, not service. This sizes a single circuit per NEC 210.20 (continuous load × 1.25 + non-continuous × 1.0). Wire pick uses the 75°C copper THHN ampacity column, with NEC 240.4(D) small-conductor caps applied (15 A on 14 AWG, 20 A on 12, 30 A on 10). For a whole-house service load, NEC Article 220 demand factors apply — that's a different calculation.

Pairs well with

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About Circuit Load Calculator

Add appliances → get the right breaker and wire size. Continuous loads get the NEC 1.25× multiplier automatically.

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