2/0 AWG voltage drop at 300 feet
Computed voltage drop for 2/0 AWG copper conductors on a 300 ft one-way run.
8.12 V
drop on 2/0 AWG copper, 300 ft one-way, 140 A load · 6.8% of 120 V · 3.4% of 240 V
2/0 AWG at 300 ft by load
| Load | Drop | % at 120 V | % at 240 V | 3% rule (240 V) |
|---|---|---|---|---|
| 35 A | 2.03 V | 1.7% | 0.8% | OK |
| 70 A | 4.06 V | 3.4% | 1.7% | OK |
| 105 A | 6.09 V | 5.1% | 2.5% | OK |
| 140 A | 8.12 V | 6.8% | 3.4% | OK at 240 V up to 5% |
Vd = 2 × length × R × I ÷ 1000, R = 0.0967 Ω/1000 ft (copper, NEC Ch. 9 Table 8). Aluminum is about 1.6× higher.
Same wire, other distances
25 ft · 50 ft · 75 ft · 100 ft · 125 ft · 150 ft · 200 ft · 250 ft
FAQ
What is the voltage drop on 2/0 AWG wire at 300 feet?
At 140 A (80% of its 175 A 75°C rating) 2/0 AWG copper drops 8.12 V over 300 ft one-way: 6.8% at 120 V or 3.4% at 240 V.
How far can I run 2/0 AWG at 140 amps?
To stay within 3% at 120 V, about 133 ft one-way; at 240 V about 266 ft.