Wire Size for 123.85 Amps
Typical copper and aluminum wire gauges for 123.85 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.
123.85A Wire Gauge by Distance
| Distance | Copper Gauge | Aluminum Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|---|
| 25 ft | 1 AWG | 2/0 AWG | 0.9536V (0.7947%) | OK |
| 50 ft | 1 AWG | 2/0 AWG | 1.91V (1.59%) | OK |
| 75 ft | 1 AWG | 2/0 AWG | 2.86V (2.38%) | OK |
| 100 ft | 1/0 AWG | 2/0 AWG | 3.02V (2.52%) | OK |
| 125 ft | 2/0 AWG | 3/0 AWG | 2.99V (2.5%) | OK |
| 150 ft | 2/0 AWG | 4/0 AWG | 3.59V (2.99%) | OK |
| 175 ft | 3/0 AWG | 4/0 AWG | 3.32V (2.77%) | OK |
| 200 ft | 4/0 AWG | 300 kcmil | 3.01V (2.51%) | OK |
| 250 ft | 250 kcmil | 500 kcmil | 3.19V (2.66%) | OK |
| 300 ft | 300 kcmil | 500 kcmil | 3.19V (2.66%) | OK |
| 400 ft | 500 kcmil | 750 kcmil | 2.56V (2.13%) | OK |
| 500 ft | 500 kcmil | 750 kcmil | 3.2V (2.66%) | 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.