Wire Size for 125.51 Amps
Typical copper and aluminum wire gauges for 125.51 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.
125.51A Wire Gauge by Distance
| Distance | Copper Gauge | Aluminum Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|---|
| 25 ft | 1 AWG | 2/0 AWG | 0.9664V (0.8054%) | OK |
| 50 ft | 1 AWG | 2/0 AWG | 1.93V (1.61%) | OK |
| 75 ft | 1 AWG | 2/0 AWG | 2.9V (2.42%) | OK |
| 100 ft | 1/0 AWG | 2/0 AWG | 3.06V (2.55%) | OK |
| 125 ft | 2/0 AWG | 3/0 AWG | 3.03V (2.53%) | OK |
| 150 ft | 3/0 AWG | 4/0 AWG | 2.88V (2.4%) | OK |
| 175 ft | 3/0 AWG | 300 kcmil | 3.36V (2.8%) | OK |
| 200 ft | 4/0 AWG | 300 kcmil | 3.05V (2.54%) | OK |
| 250 ft | 250 kcmil | 500 kcmil | 3.23V (2.69%) | OK |
| 300 ft | 300 kcmil | 500 kcmil | 3.23V (2.69%) | OK |
| 400 ft | 500 kcmil | 750 kcmil | 2.59V (2.16%) | OK |
| 500 ft | 500 kcmil | 750 kcmil | 3.24V (2.7%) | 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.