6 AWG Voltage Drop Chart
6 AWG copper wire has a resistance of 0.491 ohms per 1000 feet. NEC 240.4(D) and the standard ampacity tables cap this gauge at 65A for a branch-circuit breaker (60°C ampacity: 55A; 75°C: 65A). At 100 feet on a 120V circuit, it stays under 3% voltage drop up to about 36A.
6 AWG Wire Specifications
| Property | Value |
|---|---|
| Gauge | 6 AWG |
| Resistance (copper) | 0.491 Ω per 1000ft |
| Ampacity (60°C) | 55A |
| Ampacity (75°C) | 65A |
| NEC branch-circuit OCP | 65A |
| Amps that land on 3% drop at 100ft (120V) | ~36A |
Voltage Drop by Amps & Distance (120V)
| Amps | 50ft | 100ft | 150ft | 200ft |
|---|---|---|---|---|
| 10A | 0.4092% | 0.8183% | 1.23% | 1.64% |
| 15A | 0.6138% | 1.23% | 1.84% | 2.46% |
| 20A | 0.8183% | 1.64% | 2.46% | 3.27% |
| 25A | 1.02% | 2.05% | 3.07% | 4.09% |
| 30A | 1.23% | 2.46% | 3.68% | 4.91% |
| 40A | 1.64% | 3.27% | 4.91% | 6.55% |
| 50A | 2.05% | 4.09% | 6.14% | 8.18% |
| 60A | 2.46% | 4.91% | 7.36% | 9.82% |
| 80A | 3.27% | 6.55% | 9.82% | 13.09% |
Green = within the 3% branch-circuit drop target, Amber = 3-5% (past branch target, within 5% feeder+branch total), Red = past the 5% feeder+branch total recommendation
When to Use 6 AWG
Typical applications: Sub-panel feeders, large HVAC, EV chargers, and medium commercial loads.
Under typical 75°C-termination assumptions, 6 AWG is commonly protected by up to 65A branch-circuit OCP. Real install ceilings depend on conductor and termination temperature ratings, cable type (NM-B is limited to the 60°C column in residential use, so the usable value is lower), NEC 310.15(C)(1) bundling adjustments, and NEC 310.15(B) ambient corrections. Even with ampacity margin, longer runs may fall outside the 3% branch-circuit drop target recommended in NEC 210.19(A) Informational Note 4, which is why the distance table above matters.