Wire Size for 3.4 Amps
Typical copper wire gauges for 3.4 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 3.4A 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.
3.4A Wire Gauge by Distance
| Distance | Copper Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|
| 25 ft | 14 AWG | 0.5338V (0.4448%) | OK |
| 50 ft | 14 AWG | 1.07V (0.8897%) | OK |
| 75 ft | 14 AWG | 1.6V (1.33%) | OK |
| 100 ft | 14 AWG | 2.14V (1.78%) | OK |
| 125 ft | 14 AWG | 2.67V (2.22%) | OK |
| 150 ft | 14 AWG | 3.2V (2.67%) | OK |
| 175 ft | 12 AWG | 2.36V (1.96%) | OK |
| 200 ft | 12 AWG | 2.69V (2.24%) | OK |
| 250 ft | 12 AWG | 3.37V (2.81%) | OK |
| 300 ft | 10 AWG | 2.53V (2.11%) | OK |
| 400 ft | 10 AWG | 3.37V (2.81%) | OK |
| 500 ft | 8 AWG | 2.65V (2.2%) | 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.