Wire Size for 31.38 Amps
Typical copper and aluminum wire gauges for 31.38 amps across common run lengths on a 120V circuit, sized to keep voltage drop under 3% and respect the NEC 240.4(D) small-conductor rule. Actual install sizing depends on conductor material, insulation/termination temperature rating, cable type, ambient and bundling derates, and local code.
31.38A Wire Gauge by Distance
| Distance | Copper Gauge | Aluminum Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|---|
| 25 ft | 8 AWG | 8 AWG | 1.22V (1.02%) | OK |
| 50 ft | 8 AWG | 8 AWG | 2.44V (2.03%) | OK |
| 75 ft | 6 AWG | 6 AWG | 2.31V (1.93%) | OK |
| 100 ft | 6 AWG | 4 AWG | 3.08V (2.57%) | OK |
| 125 ft | 4 AWG | 4 AWG | 2.42V (2.01%) | OK |
| 150 ft | 4 AWG | 3 AWG | 2.9V (2.42%) | OK |
| 175 ft | 4 AWG | 2 AWG | 3.38V (2.82%) | OK |
| 200 ft | 3 AWG | 2 AWG | 3.08V (2.56%) | OK |
| 250 ft | 2 AWG | 1 AWG | 3.04V (2.54%) | OK |
| 300 ft | 1 AWG | 1/0 AWG | 2.9V (2.42%) | OK |
| 400 ft | 1/0 AWG | 2/0 AWG | 3.06V (2.55%) | OK |
| 500 ft | 2/0 AWG | 3/0 AWG | 3.03V (2.53%) | OK |
Aluminum is not typical for 10 AWG and smaller branch-circuit conductors in residential settings. Copper gauges use the NEC 240.4(D) branch-circuit cap, not raw 75°C ampacity.
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Other Amperages
This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.