Wire Size for 3.98 Amps
Typical copper wire gauges for 3.98 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 3.98A 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.
3.98A Wire Gauge by Distance
| Distance | Copper Gauge | V-Drop (Cu) | NEC Status |
|---|---|---|---|
| 25 ft | 14 AWG | 0.6249V (0.5207%) | OK |
| 50 ft | 14 AWG | 1.25V (1.04%) | OK |
| 75 ft | 14 AWG | 1.87V (1.56%) | OK |
| 100 ft | 14 AWG | 2.5V (2.08%) | OK |
| 125 ft | 14 AWG | 3.12V (2.6%) | OK |
| 150 ft | 12 AWG | 2.36V (1.97%) | OK |
| 175 ft | 12 AWG | 2.76V (2.3%) | OK |
| 200 ft | 12 AWG | 3.15V (2.63%) | OK |
| 250 ft | 10 AWG | 2.47V (2.06%) | OK |
| 300 ft | 10 AWG | 2.96V (2.47%) | OK |
| 400 ft | 8 AWG | 2.48V (2.06%) | OK |
| 500 ft | 8 AWG | 3.1V (2.58%) | 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.