Wire Size for 17.5 Amps
Typical copper wire gauges for 17.5 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. At 17.5A the load sits in residential-branch territory where aluminum is not a typical conductor, so the table lists copper only. Actual install sizing depends on conductor material, insulation/termination temperature rating, cable type, ambient and bundling derates, and local code.
17.5A Wire Gauge by Distance
| Distance | Copper Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|
| 25 ft | 12 AWG | 1.73V (1.44%) | OK |
| 50 ft | 12 AWG | 3.47V (2.89%) | OK |
| 75 ft | 10 AWG | 3.26V (2.71%) | OK |
| 100 ft | 8 AWG | 2.72V (2.27%) | OK |
| 125 ft | 8 AWG | 3.4V (2.84%) | OK |
| 150 ft | 6 AWG | 2.58V (2.15%) | OK |
| 175 ft | 6 AWG | 3.01V (2.51%) | OK |
| 200 ft | 6 AWG | 3.44V (2.86%) | OK |
| 250 ft | 4 AWG | 2.7V (2.25%) | OK |
| 300 ft | 4 AWG | 3.23V (2.7%) | OK |
| 400 ft | 3 AWG | 3.43V (2.86%) | OK |
| 500 ft | 2 AWG | 3.4V (2.83%) | OK |
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.