Wire Size for 138.57 Amps
Typical copper and aluminum wire gauges for 138.57 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.
138.57A Wire Gauge by Distance
| Distance | Copper Gauge | Aluminum Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|---|
| 25 ft | 1/0 AWG | 3/0 AWG | 0.8453V (0.7044%) | OK |
| 50 ft | 1/0 AWG | 3/0 AWG | 1.69V (1.41%) | OK |
| 75 ft | 1/0 AWG | 3/0 AWG | 2.54V (2.11%) | OK |
| 100 ft | 1/0 AWG | 3/0 AWG | 3.38V (2.82%) | OK |
| 125 ft | 2/0 AWG | 3/0 AWG | 3.35V (2.79%) | OK |
| 150 ft | 3/0 AWG | 4/0 AWG | 3.18V (2.65%) | OK |
| 175 ft | 4/0 AWG | 300 kcmil | 2.95V (2.46%) | OK |
| 200 ft | 4/0 AWG | 350 kcmil | 3.37V (2.81%) | OK |
| 250 ft | 250 kcmil | 500 kcmil | 3.57V (2.97%) | OK |
| 300 ft | 300 kcmil | 500 kcmil | 3.57V (2.97%) | OK |
| 400 ft | 500 kcmil | 750 kcmil | 2.86V (2.38%) | OK |
| 500 ft | 500 kcmil | no aluminum pick | 3.58V (2.98%) | 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.
Also Calculate
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.