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.

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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.

Like every tool on Buncha, this one runs entirely in your browser. There's no upload, no log, no record of what you've pasted or generated. Close the tab and the data is gone.

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