Voltage Drop Tables
208 volts is the standard three-phase voltage in commercial buildings supplied by a 120/208V wye-connected transformer. It is lower than 240V because of the 120-degree phase relationship between the three phases. Three-phase 208V circuits are used for commercial HVAC equipment, motors, commercial kitchen equipment, and data center power distribution.
Understanding Voltage Drop at 208V
Voltage drop is the reduction in voltage between the source (panel) and the load (device) caused by the resistance of the conductors. At 208 volts, a 3% voltage drop equals 6.2 volts, meaning the voltage at the load would be 201.8 volts. The NEC recommends keeping voltage drop below 3% for branch circuits and below 5% for the combined feeder and branch circuit. While these are recommendations rather than mandatory requirements, they represent accepted engineering practice and are enforced by most electrical inspectors.
208V three-phase voltage drop uses the 1.732 factor instead of 2. Many appliances rated for 240V will operate at 208V with reduced output (approximately 75% of rated heating capacity for resistive loads).
Common 208V circuits include: Three-phase motors, commercial HVAC, commercial kitchen equipment, data center PDUs, UPS systems, elevator motors. Each of these applications has specific NEC requirements for wire sizing, overcurrent protection, and installation methods. The tables below provide voltage drop values for copper conductors at various distances and amperages, organized by wire gauge, so you can quickly determine whether a specific gauge is adequate for your installation.
Quick Reference: Maximum Distance by Gauge at 208V
The table below shows the maximum one-way distance for each copper wire gauge at common amperages to maintain a voltage drop of 3% or less at 208 volts (three phase). If your run distance exceeds these values, you must use a larger wire gauge.
| Gauge | 20A Max Dist | 30A Max Dist | 40A Max Dist | 50A Max Dist | 60A Max Dist |
|---|---|---|---|---|---|
| 14 AWG | 57 ft | 38 ft | 28 ft | 22 ft | 19 ft |
| 12 AWG | 90 ft | 60 ft | 45 ft | 36 ft | 30 ft |
| 10 AWG | 145 ft | 96 ft | 72 ft | 58 ft | 48 ft |
| 8 AWG | 231 ft | 154 ft | 115 ft | 92 ft | 77 ft |
| 6 AWG | 366 ft | 244 ft | 183 ft | 146 ft | 122 ft |
| 4 AWG | 584 ft | 389 ft | 292 ft | 233 ft | 194 ft |
| 3 AWG | 735 ft | 490 ft | 367 ft | 294 ft | 245 ft |
| 2 AWG | 928 ft | 619 ft | 464 ft | 371 ft | 309 ft |
| 1 AWG | 1169 ft | 779 ft | 584 ft | 467 ft | 389 ft |
| 1/0 AWG | 1476 ft | 984 ft | 738 ft | 590 ft | 492 ft |
| 2/0 AWG | 1862 ft | 1241 ft | 931 ft | 745 ft | 620 ft |
| 3/0 AWG | 2351 ft | 1567 ft | 1175 ft | 940 ft | 783 ft |
| 4/0 AWG | 2962 ft | 1975 ft | 1481 ft | 1185 ft | 987 ft |
| 250 kcmil | 3497 ft | 2331 ft | 1748 ft | 1399 ft | 1165 ft |
| 300 kcmil | 4199 ft | 2799 ft | 2099 ft | 1679 ft | 1399 ft |
| 350 kcmil | 4908 ft | 3272 ft | 2454 ft | 1963 ft | 1636 ft |
| 400 kcmil | 5611 ft | 3741 ft | 2805 ft | 2244 ft | 1870 ft |
| 500 kcmil | 6982 ft | 4654 ft | 3491 ft | 2792 ft | 2327 ft |
14 AWG Voltage Drop at 208V
Voltage drop values for 14 AWG copper conductor (3.14 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 20A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 2.7V 1.3% | 4.1V 2.0% | 5.4V 2.6% | 6.8V 3.3% | 8.2V 3.9% | 10.9V 5.2% | 13.6V 6.5% |
| 50 ft | 5.4V 2.6% | 8.2V 3.9% | 10.9V 5.2% | 13.6V 6.5% | 16.3V 7.8% | 21.8V 10.5% | 27.2V 13.1% |
| 75 ft | 8.2V 3.9% | 12.2V 5.9% | 16.3V 7.8% | 20.4V 9.8% | 24.5V 11.8% | 32.6V 15.7% | 40.8V 19.6% |
| 100 ft | 10.9V 5.2% | 16.3V 7.8% | 21.8V 10.5% | 27.2V 13.1% | 32.6V 15.7% | 43.5V 20.9% | 54.4V 26.1% |
| 125 ft | 13.6V 6.5% | 20.4V 9.8% | 27.2V 13.1% | 34.0V 16.3% | 40.8V 19.6% | 54.4V 26.1% | 68.0V 32.7% |
| 150 ft | 16.3V 7.8% | 24.5V 11.8% | 32.6V 15.7% | 40.8V 19.6% | 49.0V 23.5% | 65.3V 31.4% | 81.6V 39.2% |
| 200 ft | 21.8V 10.5% | 32.6V 15.7% | 43.5V 20.9% | 54.4V 26.1% | 65.3V 31.4% | 87.0V 41.8% | 108.8V 52.3% |
| 250 ft | 27.2V 13.1% | 40.8V 19.6% | 54.4V 26.1% | 68.0V 32.7% | 81.6V 39.2% | 108.8V 52.3% | 136.0V 65.4% |
| 300 ft | 32.6V 15.7% | 49.0V 23.5% | 65.3V 31.4% | 81.6V 39.2% | 97.9V 47.1% | 130.5V 62.8% | 163.2V 78.4% |
| 400 ft | 43.5V 20.9% | 65.3V 31.4% | 87.0V 41.8% | 108.8V 52.3% | 130.5V 62.8% | 174.0V 83.7% | 217.5V 104.6% |
| 500 ft | 54.4V 26.1% | 81.6V 39.2% | 108.8V 52.3% | 136.0V 65.4% | 163.2V 78.4% | 217.5V 104.6% | 271.9V 130.7% |
12 AWG Voltage Drop at 208V
Voltage drop values for 12 AWG copper conductor (1.98 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 25A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 1.7V 0.8% | 2.6V 1.2% | 3.4V 1.6% | 4.3V 2.1% | 5.1V 2.5% | 6.9V 3.3% | 8.6V 4.1% |
| 50 ft | 3.4V 1.6% | 5.1V 2.5% | 6.9V 3.3% | 8.6V 4.1% | 10.3V 5.0% | 13.7V 6.6% | 17.1V 8.2% |
| 75 ft | 5.1V 2.5% | 7.7V 3.7% | 10.3V 5.0% | 12.9V 6.2% | 15.4V 7.4% | 20.6V 9.9% | 25.7V 12.4% |
| 100 ft | 6.9V 3.3% | 10.3V 5.0% | 13.7V 6.6% | 17.1V 8.2% | 20.6V 9.9% | 27.4V 13.2% | 34.3V 16.5% |
| 125 ft | 8.6V 4.1% | 12.9V 6.2% | 17.1V 8.2% | 21.4V 10.3% | 25.7V 12.4% | 34.3V 16.5% | 42.9V 20.6% |
| 150 ft | 10.3V 5.0% | 15.4V 7.4% | 20.6V 9.9% | 25.7V 12.4% | 30.9V 14.8% | 41.1V 19.8% | 51.4V 24.7% |
| 200 ft | 13.7V 6.6% | 20.6V 9.9% | 27.4V 13.2% | 34.3V 16.5% | 41.1V 19.8% | 54.9V 26.4% | 68.6V 33.0% |
| 250 ft | 17.1V 8.2% | 25.7V 12.4% | 34.3V 16.5% | 42.9V 20.6% | 51.4V 24.7% | 68.6V 33.0% | 85.7V 41.2% |
| 300 ft | 20.6V 9.9% | 30.9V 14.8% | 41.1V 19.8% | 51.4V 24.7% | 61.7V 29.7% | 82.3V 39.6% | 102.9V 49.5% |
| 400 ft | 27.4V 13.2% | 41.1V 19.8% | 54.9V 26.4% | 68.6V 33.0% | 82.3V 39.6% | 109.7V 52.8% | 137.2V 66.0% |
| 500 ft | 34.3V 16.5% | 51.4V 24.7% | 68.6V 33.0% | 85.7V 41.2% | 102.9V 49.5% | 137.2V 66.0% | 171.5V 82.4% |
10 AWG Voltage Drop at 208V
Voltage drop values for 10 AWG copper conductor (1.24 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 35A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 1.1V 0.5% | 1.6V 0.8% | 2.1V 1.0% | 2.7V 1.3% | 3.2V 1.6% | 4.3V 2.1% | 5.4V 2.6% |
| 50 ft | 2.1V 1.0% | 3.2V 1.6% | 4.3V 2.1% | 5.4V 2.6% | 6.4V 3.1% | 8.6V 4.1% | 10.7V 5.2% |
| 75 ft | 3.2V 1.6% | 4.8V 2.3% | 6.4V 3.1% | 8.1V 3.9% | 9.7V 4.7% | 12.9V 6.2% | 16.1V 7.7% |
| 100 ft | 4.3V 2.1% | 6.4V 3.1% | 8.6V 4.1% | 10.7V 5.2% | 12.9V 6.2% | 17.2V 8.3% | 21.5V 10.3% |
| 125 ft | 5.4V 2.6% | 8.1V 3.9% | 10.7V 5.2% | 13.4V 6.5% | 16.1V 7.7% | 21.5V 10.3% | 26.9V 12.9% |
| 150 ft | 6.4V 3.1% | 9.7V 4.7% | 12.9V 6.2% | 16.1V 7.7% | 19.3V 9.3% | 25.8V 12.4% | 32.2V 15.5% |
| 200 ft | 8.6V 4.1% | 12.9V 6.2% | 17.2V 8.3% | 21.5V 10.3% | 25.8V 12.4% | 34.4V 16.5% | 43.0V 20.6% |
| 250 ft | 10.7V 5.2% | 16.1V 7.7% | 21.5V 10.3% | 26.9V 12.9% | 32.2V 15.5% | 43.0V 20.6% | 53.7V 25.8% |
| 300 ft | 12.9V 6.2% | 19.3V 9.3% | 25.8V 12.4% | 32.2V 15.5% | 38.7V 18.6% | 51.5V 24.8% | 64.4V 31.0% |
| 400 ft | 17.2V 8.3% | 25.8V 12.4% | 34.4V 16.5% | 43.0V 20.6% | 51.5V 24.8% | 68.7V 33.0% | 85.9V 41.3% |
| 500 ft | 21.5V 10.3% | 32.2V 15.5% | 43.0V 20.6% | 53.7V 25.8% | 64.4V 31.0% | 85.9V 41.3% | 107.4V 51.6% |
8 AWG Voltage Drop at 208V
Voltage drop values for 8 AWG copper conductor (0.778 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 50A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.7V 0.3% | 1.0V 0.5% | 1.4V 0.7% | 1.7V 0.8% | 2.0V 1.0% | 2.7V 1.3% | 3.4V 1.6% |
| 50 ft | 1.4V 0.7% | 2.0V 1.0% | 2.7V 1.3% | 3.4V 1.6% | 4.0V 1.9% | 5.4V 2.6% | 6.7V 3.2% |
| 75 ft | 2.0V 1.0% | 3.0V 1.5% | 4.0V 1.9% | 5.0V 2.4% | 6.1V 2.9% | 8.1V 3.9% | 10.1V 4.9% |
| 100 ft | 2.7V 1.3% | 4.0V 1.9% | 5.4V 2.6% | 6.7V 3.2% | 8.1V 3.9% | 10.8V 5.2% | 13.5V 6.5% |
| 125 ft | 3.4V 1.6% | 5.0V 2.4% | 6.7V 3.2% | 8.4V 4.0% | 10.1V 4.9% | 13.5V 6.5% | 16.8V 8.1% |
| 150 ft | 4.0V 1.9% | 6.1V 2.9% | 8.1V 3.9% | 10.1V 4.9% | 12.1V 5.8% | 16.2V 7.8% | 20.2V 9.7% |
| 200 ft | 5.4V 2.6% | 8.1V 3.9% | 10.8V 5.2% | 13.5V 6.5% | 16.2V 7.8% | 21.6V 10.4% | 26.9V 13.0% |
| 250 ft | 6.7V 3.2% | 10.1V 4.9% | 13.5V 6.5% | 16.8V 8.1% | 20.2V 9.7% | 26.9V 13.0% | 33.7V 16.2% |
| 300 ft | 8.1V 3.9% | 12.1V 5.8% | 16.2V 7.8% | 20.2V 9.7% | 24.3V 11.7% | 32.3V 15.6% | 40.4V 19.4% |
| 400 ft | 10.8V 5.2% | 16.2V 7.8% | 21.6V 10.4% | 26.9V 13.0% | 32.3V 15.6% | 43.1V 20.7% | 53.9V 25.9% |
| 500 ft | 13.5V 6.5% | 20.2V 9.7% | 26.9V 13.0% | 33.7V 16.2% | 40.4V 19.4% | 53.9V 25.9% | 67.4V 32.4% |
6 AWG Voltage Drop at 208V
Voltage drop values for 6 AWG copper conductor (0.491 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 65A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.4V 0.2% | 0.6V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% |
| 50 ft | 0.8V 0.4% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% | 2.5V 1.2% | 3.4V 1.6% | 4.3V 2.0% |
| 75 ft | 1.3V 0.6% | 1.9V 0.9% | 2.5V 1.2% | 3.2V 1.5% | 3.8V 1.8% | 5.1V 2.5% | 6.4V 3.1% |
| 100 ft | 1.7V 0.8% | 2.5V 1.2% | 3.4V 1.6% | 4.3V 2.0% | 5.1V 2.5% | 6.8V 3.3% | 8.5V 4.1% |
| 125 ft | 2.1V 1.0% | 3.2V 1.5% | 4.3V 2.0% | 5.3V 2.6% | 6.4V 3.1% | 8.5V 4.1% | 10.6V 5.1% |
| 150 ft | 2.5V 1.2% | 3.8V 1.8% | 5.1V 2.5% | 6.4V 3.1% | 7.7V 3.7% | 10.2V 4.9% | 12.8V 6.1% |
| 200 ft | 3.4V 1.6% | 5.1V 2.5% | 6.8V 3.3% | 8.5V 4.1% | 10.2V 4.9% | 13.6V 6.5% | 17.0V 8.2% |
| 250 ft | 4.3V 2.0% | 6.4V 3.1% | 8.5V 4.1% | 10.6V 5.1% | 12.8V 6.1% | 17.0V 8.2% | 21.3V 10.2% |
| 300 ft | 5.1V 2.5% | 7.7V 3.7% | 10.2V 4.9% | 12.8V 6.1% | 15.3V 7.4% | 20.4V 9.8% | 25.5V 12.3% |
| 400 ft | 6.8V 3.3% | 10.2V 4.9% | 13.6V 6.5% | 17.0V 8.2% | 20.4V 9.8% | 27.2V 13.1% | 34.0V 16.4% |
| 500 ft | 8.5V 4.1% | 12.8V 6.1% | 17.0V 8.2% | 21.3V 10.2% | 25.5V 12.3% | 34.0V 16.4% | 42.5V 20.4% |
4 AWG Voltage Drop at 208V
Voltage drop values for 4 AWG copper conductor (0.308 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 85A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.3V 0.1% | 0.4V 0.2% | 0.5V 0.3% | 0.7V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% |
| 50 ft | 0.5V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.6V 0.8% | 2.1V 1.0% | 2.7V 1.3% |
| 75 ft | 0.8V 0.4% | 1.2V 0.6% | 1.6V 0.8% | 2.0V 1.0% | 2.4V 1.1% | 3.2V 1.5% | 4.0V 1.9% |
| 100 ft | 1.1V 0.5% | 1.6V 0.8% | 2.1V 1.0% | 2.7V 1.3% | 3.2V 1.5% | 4.3V 2.0% | 5.3V 2.6% |
| 125 ft | 1.3V 0.6% | 2.0V 1.0% | 2.7V 1.3% | 3.3V 1.6% | 4.0V 1.9% | 5.3V 2.6% | 6.7V 3.2% |
| 150 ft | 1.6V 0.8% | 2.4V 1.1% | 3.2V 1.5% | 4.0V 1.9% | 4.8V 2.3% | 6.4V 3.1% | 8.0V 3.9% |
| 200 ft | 2.1V 1.0% | 3.2V 1.5% | 4.3V 2.0% | 5.3V 2.6% | 6.4V 3.1% | 8.5V 4.1% | 10.7V 5.1% |
| 250 ft | 2.7V 1.3% | 4.0V 1.9% | 5.3V 2.6% | 6.7V 3.2% | 8.0V 3.9% | 10.7V 5.1% | 13.3V 6.4% |
| 300 ft | 3.2V 1.5% | 4.8V 2.3% | 6.4V 3.1% | 8.0V 3.9% | 9.6V 4.6% | 12.8V 6.2% | 16.0V 7.7% |
| 400 ft | 4.3V 2.0% | 6.4V 3.1% | 8.5V 4.1% | 10.7V 5.1% | 12.8V 6.2% | 17.1V 8.2% | 21.3V 10.3% |
| 500 ft | 5.3V 2.6% | 8.0V 3.9% | 10.7V 5.1% | 13.3V 6.4% | 16.0V 7.7% | 21.3V 10.3% | 26.7V 12.8% |
3 AWG Voltage Drop at 208V
Voltage drop values for 3 AWG copper conductor (0.245 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 100A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.2V 0.1% | 0.3V 0.1% | 0.4V 0.2% | 0.5V 0.3% | 0.6V 0.3% | 0.8V 0.4% | 1.1V 0.5% |
| 50 ft | 0.4V 0.2% | 0.6V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% |
| 75 ft | 0.6V 0.3% | 0.9V 0.5% | 1.3V 0.6% | 1.6V 0.8% | 1.9V 0.9% | 2.5V 1.2% | 3.2V 1.5% |
| 100 ft | 0.8V 0.4% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% |
| 125 ft | 1.1V 0.5% | 1.6V 0.8% | 2.1V 1.0% | 2.6V 1.3% | 3.2V 1.5% | 4.2V 2.0% | 5.3V 2.5% |
| 150 ft | 1.3V 0.6% | 1.9V 0.9% | 2.5V 1.2% | 3.2V 1.5% | 3.8V 1.8% | 5.1V 2.5% | 6.4V 3.1% |
| 200 ft | 1.7V 0.8% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% | 5.1V 2.5% | 6.8V 3.3% | 8.5V 4.1% |
| 250 ft | 2.1V 1.0% | 3.2V 1.5% | 4.2V 2.0% | 5.3V 2.5% | 6.4V 3.1% | 8.5V 4.1% | 10.6V 5.1% |
| 300 ft | 2.5V 1.2% | 3.8V 1.8% | 5.1V 2.5% | 6.4V 3.1% | 7.6V 3.7% | 10.2V 4.9% | 12.7V 6.1% |
| 400 ft | 3.4V 1.6% | 5.1V 2.5% | 6.8V 3.3% | 8.5V 4.1% | 10.2V 4.9% | 13.6V 6.5% | 17.0V 8.2% |
| 500 ft | 4.2V 2.0% | 6.4V 3.1% | 8.5V 4.1% | 10.6V 5.1% | 12.7V 6.1% | 17.0V 8.2% | 21.2V 10.2% |
2 AWG Voltage Drop at 208V
Voltage drop values for 2 AWG copper conductor (0.194 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 115A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.2V 0.1% | 0.3V 0.1% | 0.3V 0.2% | 0.4V 0.2% | 0.5V 0.2% | 0.7V 0.3% | 0.8V 0.4% |
| 50 ft | 0.3V 0.2% | 0.5V 0.2% | 0.7V 0.3% | 0.8V 0.4% | 1.0V 0.5% | 1.3V 0.7% | 1.7V 0.8% |
| 75 ft | 0.5V 0.2% | 0.8V 0.4% | 1.0V 0.5% | 1.3V 0.6% | 1.5V 0.7% | 2.0V 1.0% | 2.5V 1.2% |
| 100 ft | 0.7V 0.3% | 1.0V 0.5% | 1.3V 0.7% | 1.7V 0.8% | 2.0V 1.0% | 2.7V 1.3% | 3.4V 1.6% |
| 125 ft | 0.8V 0.4% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% |
| 150 ft | 1.0V 0.5% | 1.5V 0.7% | 2.0V 1.0% | 2.5V 1.2% | 3.0V 1.4% | 4.0V 1.9% | 5.0V 2.4% |
| 200 ft | 1.3V 0.7% | 2.0V 1.0% | 2.7V 1.3% | 3.4V 1.6% | 4.0V 1.9% | 5.4V 2.6% | 6.7V 3.2% |
| 250 ft | 1.7V 0.8% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% | 5.0V 2.4% | 6.7V 3.2% | 8.4V 4.0% |
| 300 ft | 2.0V 1.0% | 3.0V 1.4% | 4.0V 1.9% | 5.0V 2.4% | 6.0V 2.9% | 8.1V 3.9% | 10.1V 4.8% |
| 400 ft | 2.7V 1.3% | 4.0V 1.9% | 5.4V 2.6% | 6.7V 3.2% | 8.1V 3.9% | 10.8V 5.2% | 13.4V 6.5% |
| 500 ft | 3.4V 1.6% | 5.0V 2.4% | 6.7V 3.2% | 8.4V 4.0% | 10.1V 4.8% | 13.4V 6.5% | 16.8V 8.1% |
1 AWG Voltage Drop at 208V
Voltage drop values for 1 AWG copper conductor (0.154 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 130A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.1V 0.1% | 0.2V 0.1% | 0.3V 0.1% | 0.3V 0.2% | 0.4V 0.2% | 0.5V 0.3% | 0.7V 0.3% |
| 50 ft | 0.3V 0.1% | 0.4V 0.2% | 0.5V 0.3% | 0.7V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% |
| 75 ft | 0.4V 0.2% | 0.6V 0.3% | 0.8V 0.4% | 1.0V 0.5% | 1.2V 0.6% | 1.6V 0.8% | 2.0V 1.0% |
| 100 ft | 0.5V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.6V 0.8% | 2.1V 1.0% | 2.7V 1.3% |
| 125 ft | 0.7V 0.3% | 1.0V 0.5% | 1.3V 0.6% | 1.7V 0.8% | 2.0V 1.0% | 2.7V 1.3% | 3.3V 1.6% |
| 150 ft | 0.8V 0.4% | 1.2V 0.6% | 1.6V 0.8% | 2.0V 1.0% | 2.4V 1.1% | 3.2V 1.5% | 4.0V 1.9% |
| 200 ft | 1.1V 0.5% | 1.6V 0.8% | 2.1V 1.0% | 2.7V 1.3% | 3.2V 1.5% | 4.3V 2.0% | 5.3V 2.6% |
| 250 ft | 1.3V 0.6% | 2.0V 1.0% | 2.7V 1.3% | 3.3V 1.6% | 4.0V 1.9% | 5.3V 2.6% | 6.7V 3.2% |
| 300 ft | 1.6V 0.8% | 2.4V 1.1% | 3.2V 1.5% | 4.0V 1.9% | 4.8V 2.3% | 6.4V 3.1% | 8.0V 3.9% |
| 400 ft | 2.1V 1.0% | 3.2V 1.5% | 4.3V 2.0% | 5.3V 2.6% | 6.4V 3.1% | 8.5V 4.1% | 10.7V 5.1% |
| 500 ft | 2.7V 1.3% | 4.0V 1.9% | 5.3V 2.6% | 6.7V 3.2% | 8.0V 3.9% | 10.7V 5.1% | 13.3V 6.4% |
1/0 AWG Voltage Drop at 208V
Voltage drop values for 1/0 AWG copper conductor (0.122 ohms/kft) at 208 volts, three phase. Ampacity at 75°C: 150A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.1V 0.1% | 0.2V 0.1% | 0.2V 0.1% | 0.3V 0.1% | 0.3V 0.1% | 0.4V 0.2% | 0.5V 0.3% |
| 50 ft | 0.2V 0.1% | 0.3V 0.1% | 0.4V 0.2% | 0.5V 0.3% | 0.6V 0.3% | 0.8V 0.4% | 1.1V 0.5% |
| 75 ft | 0.3V 0.1% | 0.5V 0.2% | 0.6V 0.3% | 0.8V 0.4% | 0.9V 0.5% | 1.3V 0.6% | 1.6V 0.8% |
| 100 ft | 0.4V 0.2% | 0.6V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% |
| 125 ft | 0.5V 0.3% | 0.8V 0.4% | 1.1V 0.5% | 1.3V 0.6% | 1.6V 0.8% | 2.1V 1.0% | 2.6V 1.3% |
| 150 ft | 0.6V 0.3% | 0.9V 0.5% | 1.3V 0.6% | 1.6V 0.8% | 1.9V 0.9% | 2.5V 1.2% | 3.2V 1.5% |
| 200 ft | 0.8V 0.4% | 1.3V 0.6% | 1.7V 0.8% | 2.1V 1.0% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% |
| 250 ft | 1.1V 0.5% | 1.6V 0.8% | 2.1V 1.0% | 2.6V 1.3% | 3.2V 1.5% | 4.2V 2.0% | 5.3V 2.5% |
| 300 ft | 1.3V 0.6% | 1.9V 0.9% | 2.5V 1.2% | 3.2V 1.5% | 3.8V 1.8% | 5.1V 2.4% | 6.3V 3.0% |
| 400 ft | 1.7V 0.8% | 2.5V 1.2% | 3.4V 1.6% | 4.2V 2.0% | 5.1V 2.4% | 6.8V 3.3% | 8.4V 4.1% |
| 500 ft | 2.1V 1.0% | 3.2V 1.5% | 4.2V 2.0% | 5.3V 2.5% | 6.3V 3.0% | 8.4V 4.1% | 10.6V 5.1% |
Other Voltage Levels
View voltage drop tables for other standard voltages. Higher voltages result in lower percentage voltage drop for the same absolute voltage loss, which allows longer conductor runs without upsizing.
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