Voltage Drop Tables
240 volts is used for large residential appliances and equipment that require more power than a 120-volt circuit can efficiently deliver. A 240-volt circuit uses both hot conductors from the main service panel. Common 240-volt loads include electric ranges, clothes dryers, water heaters, air conditioners, electric vehicle chargers, hot tubs, and subpanel feeders.
Understanding Voltage Drop at 240V
Voltage drop is the reduction in voltage between the source (panel) and the load (device) caused by the resistance of the conductors. At 240 volts, a 3% voltage drop equals 7.2 volts, meaning the voltage at the load would be 232.8 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.
240V circuits use two-pole breakers and carry current on both hot conductors. Because the voltage is doubled compared to 120V, the percentage voltage drop is halved for the same absolute voltage loss, allowing longer conductor runs.
Common 240V circuits include: 30A dryer, 40-50A range, 30-40A AC unit, 50-60A EV charger, 60-200A subpanels, 30A well pump, 50A welder, 30-50A hot tub, 200A service entrance. 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 240V
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 240 volts (single 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 | 734 ft | 489 ft | 367 ft | 293 ft | 244 ft |
| 2 AWG | 927 ft | 618 ft | 463 ft | 371 ft | 309 ft |
| 1 AWG | 1168 ft | 779 ft | 584 ft | 467 ft | 389 ft |
| 1/0 AWG | 1475 ft | 983 ft | 737 ft | 590 ft | 491 ft |
| 2/0 AWG | 1861 ft | 1240 ft | 930 ft | 744 ft | 620 ft |
| 3/0 AWG | 2349 ft | 1566 ft | 1174 ft | 939 ft | 783 ft |
| 4/0 AWG | 2960 ft | 1973 ft | 1480 ft | 1184 ft | 986 ft |
| 250 kcmil | 3495 ft | 2330 ft | 1747 ft | 1398 ft | 1165 ft |
| 300 kcmil | 4195 ft | 2797 ft | 2097 ft | 1678 ft | 1398 ft |
| 350 kcmil | 4904 ft | 3269 ft | 2452 ft | 1961 ft | 1634 ft |
| 400 kcmil | 5607 ft | 3738 ft | 2803 ft | 2242 ft | 1869 ft |
| 500 kcmil | 6976 ft | 4651 ft | 3488 ft | 2790 ft | 2325 ft |
14 AWG Voltage Drop at 240V
Voltage drop values for 14 AWG copper conductor (3.14 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 20A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 3.1V 1.3% | 4.7V 2.0% | 6.3V 2.6% | 7.8V 3.3% | 9.4V 3.9% | 12.6V 5.2% | 15.7V 6.5% |
| 50 ft | 6.3V 2.6% | 9.4V 3.9% | 12.6V 5.2% | 15.7V 6.5% | 18.8V 7.8% | 25.1V 10.5% | 31.4V 13.1% |
| 75 ft | 9.4V 3.9% | 14.1V 5.9% | 18.8V 7.8% | 23.6V 9.8% | 28.3V 11.8% | 37.7V 15.7% | 47.1V 19.6% |
| 100 ft | 12.6V 5.2% | 18.8V 7.8% | 25.1V 10.5% | 31.4V 13.1% | 37.7V 15.7% | 50.2V 20.9% | 62.8V 26.2% |
| 125 ft | 15.7V 6.5% | 23.6V 9.8% | 31.4V 13.1% | 39.3V 16.4% | 47.1V 19.6% | 62.8V 26.2% | 78.5V 32.7% |
| 150 ft | 18.8V 7.8% | 28.3V 11.8% | 37.7V 15.7% | 47.1V 19.6% | 56.5V 23.6% | 75.4V 31.4% | 94.2V 39.3% |
| 200 ft | 25.1V 10.5% | 37.7V 15.7% | 50.2V 20.9% | 62.8V 26.2% | 75.4V 31.4% | 100.5V 41.9% | 125.6V 52.3% |
| 250 ft | 31.4V 13.1% | 47.1V 19.6% | 62.8V 26.2% | 78.5V 32.7% | 94.2V 39.3% | 125.6V 52.3% | 157.0V 65.4% |
| 300 ft | 37.7V 15.7% | 56.5V 23.6% | 75.4V 31.4% | 94.2V 39.3% | 113.0V 47.1% | 150.7V 62.8% | 188.4V 78.5% |
| 400 ft | 50.2V 20.9% | 75.4V 31.4% | 100.5V 41.9% | 125.6V 52.3% | 150.7V 62.8% | 201.0V 83.7% | 251.2V 104.7% |
| 500 ft | 62.8V 26.2% | 94.2V 39.3% | 125.6V 52.3% | 157.0V 65.4% | 188.4V 78.5% | 251.2V 104.7% | 314.0V 130.8% |
12 AWG Voltage Drop at 240V
Voltage drop values for 12 AWG copper conductor (1.98 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 25A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 2.0V 0.8% | 3.0V 1.2% | 4.0V 1.6% | 5.0V 2.1% | 5.9V 2.5% | 7.9V 3.3% | 9.9V 4.1% |
| 50 ft | 4.0V 1.6% | 5.9V 2.5% | 7.9V 3.3% | 9.9V 4.1% | 11.9V 5.0% | 15.8V 6.6% | 19.8V 8.3% |
| 75 ft | 5.9V 2.5% | 8.9V 3.7% | 11.9V 5.0% | 14.8V 6.2% | 17.8V 7.4% | 23.8V 9.9% | 29.7V 12.4% |
| 100 ft | 7.9V 3.3% | 11.9V 5.0% | 15.8V 6.6% | 19.8V 8.3% | 23.8V 9.9% | 31.7V 13.2% | 39.6V 16.5% |
| 125 ft | 9.9V 4.1% | 14.8V 6.2% | 19.8V 8.3% | 24.8V 10.3% | 29.7V 12.4% | 39.6V 16.5% | 49.5V 20.6% |
| 150 ft | 11.9V 5.0% | 17.8V 7.4% | 23.8V 9.9% | 29.7V 12.4% | 35.6V 14.8% | 47.5V 19.8% | 59.4V 24.8% |
| 200 ft | 15.8V 6.6% | 23.8V 9.9% | 31.7V 13.2% | 39.6V 16.5% | 47.5V 19.8% | 63.4V 26.4% | 79.2V 33.0% |
| 250 ft | 19.8V 8.3% | 29.7V 12.4% | 39.6V 16.5% | 49.5V 20.6% | 59.4V 24.8% | 79.2V 33.0% | 99.0V 41.3% |
| 300 ft | 23.8V 9.9% | 35.6V 14.8% | 47.5V 19.8% | 59.4V 24.8% | 71.3V 29.7% | 95.0V 39.6% | 118.8V 49.5% |
| 400 ft | 31.7V 13.2% | 47.5V 19.8% | 63.4V 26.4% | 79.2V 33.0% | 95.0V 39.6% | 126.7V 52.8% | 158.4V 66.0% |
| 500 ft | 39.6V 16.5% | 59.4V 24.8% | 79.2V 33.0% | 99.0V 41.3% | 118.8V 49.5% | 158.4V 66.0% | 198.0V 82.5% |
10 AWG Voltage Drop at 240V
Voltage drop values for 10 AWG copper conductor (1.24 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 35A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 1.2V 0.5% | 1.9V 0.8% | 2.5V 1.0% | 3.1V 1.3% | 3.7V 1.6% | 5.0V 2.1% | 6.2V 2.6% |
| 50 ft | 2.5V 1.0% | 3.7V 1.6% | 5.0V 2.1% | 6.2V 2.6% | 7.4V 3.1% | 9.9V 4.1% | 12.4V 5.2% |
| 75 ft | 3.7V 1.6% | 5.6V 2.3% | 7.4V 3.1% | 9.3V 3.9% | 11.2V 4.7% | 14.9V 6.2% | 18.6V 7.8% |
| 100 ft | 5.0V 2.1% | 7.4V 3.1% | 9.9V 4.1% | 12.4V 5.2% | 14.9V 6.2% | 19.8V 8.3% | 24.8V 10.3% |
| 125 ft | 6.2V 2.6% | 9.3V 3.9% | 12.4V 5.2% | 15.5V 6.5% | 18.6V 7.8% | 24.8V 10.3% | 31.0V 12.9% |
| 150 ft | 7.4V 3.1% | 11.2V 4.7% | 14.9V 6.2% | 18.6V 7.8% | 22.3V 9.3% | 29.8V 12.4% | 37.2V 15.5% |
| 200 ft | 9.9V 4.1% | 14.9V 6.2% | 19.8V 8.3% | 24.8V 10.3% | 29.8V 12.4% | 39.7V 16.5% | 49.6V 20.7% |
| 250 ft | 12.4V 5.2% | 18.6V 7.8% | 24.8V 10.3% | 31.0V 12.9% | 37.2V 15.5% | 49.6V 20.7% | 62.0V 25.8% |
| 300 ft | 14.9V 6.2% | 22.3V 9.3% | 29.8V 12.4% | 37.2V 15.5% | 44.6V 18.6% | 59.5V 24.8% | 74.4V 31.0% |
| 400 ft | 19.8V 8.3% | 29.8V 12.4% | 39.7V 16.5% | 49.6V 20.7% | 59.5V 24.8% | 79.4V 33.1% | 99.2V 41.3% |
| 500 ft | 24.8V 10.3% | 37.2V 15.5% | 49.6V 20.7% | 62.0V 25.8% | 74.4V 31.0% | 99.2V 41.3% | 124.0V 51.7% |
8 AWG Voltage Drop at 240V
Voltage drop values for 8 AWG copper conductor (0.778 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 50A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.8V 0.3% | 1.2V 0.5% | 1.6V 0.7% | 1.9V 0.8% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% |
| 50 ft | 1.6V 0.7% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% | 4.7V 1.9% | 6.2V 2.6% | 7.8V 3.2% |
| 75 ft | 2.3V 1.0% | 3.5V 1.5% | 4.7V 1.9% | 5.8V 2.4% | 7.0V 2.9% | 9.3V 3.9% | 11.7V 4.9% |
| 100 ft | 3.1V 1.3% | 4.7V 1.9% | 6.2V 2.6% | 7.8V 3.2% | 9.3V 3.9% | 12.4V 5.2% | 15.6V 6.5% |
| 125 ft | 3.9V 1.6% | 5.8V 2.4% | 7.8V 3.2% | 9.7V 4.0% | 11.7V 4.9% | 15.6V 6.5% | 19.4V 8.1% |
| 150 ft | 4.7V 1.9% | 7.0V 2.9% | 9.3V 3.9% | 11.7V 4.9% | 14.0V 5.8% | 18.7V 7.8% | 23.3V 9.7% |
| 200 ft | 6.2V 2.6% | 9.3V 3.9% | 12.4V 5.2% | 15.6V 6.5% | 18.7V 7.8% | 24.9V 10.4% | 31.1V 13.0% |
| 250 ft | 7.8V 3.2% | 11.7V 4.9% | 15.6V 6.5% | 19.4V 8.1% | 23.3V 9.7% | 31.1V 13.0% | 38.9V 16.2% |
| 300 ft | 9.3V 3.9% | 14.0V 5.8% | 18.7V 7.8% | 23.3V 9.7% | 28.0V 11.7% | 37.3V 15.6% | 46.7V 19.4% |
| 400 ft | 12.4V 5.2% | 18.7V 7.8% | 24.9V 10.4% | 31.1V 13.0% | 37.3V 15.6% | 49.8V 20.8% | 62.2V 25.9% |
| 500 ft | 15.6V 6.5% | 23.3V 9.7% | 31.1V 13.0% | 38.9V 16.2% | 46.7V 19.4% | 62.2V 25.9% | 77.8V 32.4% |
6 AWG Voltage Drop at 240V
Voltage drop values for 6 AWG copper conductor (0.491 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 65A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.5V 0.2% | 0.7V 0.3% | 1.0V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 2.0V 0.8% | 2.5V 1.0% |
| 50 ft | 1.0V 0.4% | 1.5V 0.6% | 2.0V 0.8% | 2.5V 1.0% | 3.0V 1.2% | 3.9V 1.6% | 4.9V 2.0% |
| 75 ft | 1.5V 0.6% | 2.2V 0.9% | 3.0V 1.2% | 3.7V 1.5% | 4.4V 1.8% | 5.9V 2.5% | 7.4V 3.1% |
| 100 ft | 2.0V 0.8% | 3.0V 1.2% | 3.9V 1.6% | 4.9V 2.0% | 5.9V 2.5% | 7.9V 3.3% | 9.8V 4.1% |
| 125 ft | 2.5V 1.0% | 3.7V 1.5% | 4.9V 2.0% | 6.1V 2.6% | 7.4V 3.1% | 9.8V 4.1% | 12.3V 5.1% |
| 150 ft | 3.0V 1.2% | 4.4V 1.8% | 5.9V 2.5% | 7.4V 3.1% | 8.8V 3.7% | 11.8V 4.9% | 14.7V 6.1% |
| 200 ft | 3.9V 1.6% | 5.9V 2.5% | 7.9V 3.3% | 9.8V 4.1% | 11.8V 4.9% | 15.7V 6.5% | 19.6V 8.2% |
| 250 ft | 4.9V 2.0% | 7.4V 3.1% | 9.8V 4.1% | 12.3V 5.1% | 14.7V 6.1% | 19.6V 8.2% | 24.6V 10.2% |
| 300 ft | 5.9V 2.5% | 8.8V 3.7% | 11.8V 4.9% | 14.7V 6.1% | 17.7V 7.4% | 23.6V 9.8% | 29.5V 12.3% |
| 400 ft | 7.9V 3.3% | 11.8V 4.9% | 15.7V 6.5% | 19.6V 8.2% | 23.6V 9.8% | 31.4V 13.1% | 39.3V 16.4% |
| 500 ft | 9.8V 4.1% | 14.7V 6.1% | 19.6V 8.2% | 24.6V 10.2% | 29.5V 12.3% | 39.3V 16.4% | 49.1V 20.5% |
4 AWG Voltage Drop at 240V
Voltage drop values for 4 AWG copper conductor (0.308 ohms/kft) at 240 volts, single 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% | 0.5V 0.2% | 0.6V 0.3% | 0.8V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% |
| 50 ft | 0.6V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 1.9V 0.8% | 2.5V 1.0% | 3.1V 1.3% |
| 75 ft | 0.9V 0.4% | 1.4V 0.6% | 1.9V 0.8% | 2.3V 1.0% | 2.8V 1.2% | 3.7V 1.5% | 4.6V 1.9% |
| 100 ft | 1.2V 0.5% | 1.9V 0.8% | 2.5V 1.0% | 3.1V 1.3% | 3.7V 1.5% | 4.9V 2.0% | 6.2V 2.6% |
| 125 ft | 1.5V 0.6% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% | 4.6V 1.9% | 6.2V 2.6% | 7.7V 3.2% |
| 150 ft | 1.9V 0.8% | 2.8V 1.2% | 3.7V 1.5% | 4.6V 1.9% | 5.5V 2.3% | 7.4V 3.1% | 9.2V 3.9% |
| 200 ft | 2.5V 1.0% | 3.7V 1.5% | 4.9V 2.0% | 6.2V 2.6% | 7.4V 3.1% | 9.9V 4.1% | 12.3V 5.1% |
| 250 ft | 3.1V 1.3% | 4.6V 1.9% | 6.2V 2.6% | 7.7V 3.2% | 9.2V 3.9% | 12.3V 5.1% | 15.4V 6.4% |
| 300 ft | 3.7V 1.5% | 5.5V 2.3% | 7.4V 3.1% | 9.2V 3.9% | 11.1V 4.6% | 14.8V 6.2% | 18.5V 7.7% |
| 400 ft | 4.9V 2.0% | 7.4V 3.1% | 9.9V 4.1% | 12.3V 5.1% | 14.8V 6.2% | 19.7V 8.2% | 24.6V 10.3% |
| 500 ft | 6.2V 2.6% | 9.2V 3.9% | 12.3V 5.1% | 15.4V 6.4% | 18.5V 7.7% | 24.6V 10.3% | 30.8V 12.8% |
3 AWG Voltage Drop at 240V
Voltage drop values for 3 AWG copper conductor (0.245 ohms/kft) at 240 volts, single phase. Ampacity at 75°C: 100A. Cells in red exceed the 3% NEC recommendation.
| Distance | 20A | 30A | 40A | 50A | 60A | 80A | 100A |
|---|---|---|---|---|---|---|---|
| 25 ft | 0.3V 0.1% | 0.4V 0.1% | 0.5V 0.2% | 0.6V 0.3% | 0.7V 0.3% | 1.0V 0.4% | 1.2V 0.5% |
| 50 ft | 0.5V 0.2% | 0.7V 0.3% | 1.0V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 2.0V 0.8% | 2.5V 1.0% |
| 75 ft | 0.7V 0.3% | 1.1V 0.5% | 1.5V 0.6% | 1.8V 0.8% | 2.2V 0.9% | 2.9V 1.2% | 3.7V 1.5% |
| 100 ft | 1.0V 0.4% | 1.5V 0.6% | 2.0V 0.8% | 2.5V 1.0% | 2.9V 1.2% | 3.9V 1.6% | 4.9V 2.0% |
| 125 ft | 1.2V 0.5% | 1.8V 0.8% | 2.5V 1.0% | 3.1V 1.3% | 3.7V 1.5% | 4.9V 2.0% | 6.1V 2.5% |
| 150 ft | 1.5V 0.6% | 2.2V 0.9% | 2.9V 1.2% | 3.7V 1.5% | 4.4V 1.8% | 5.9V 2.5% | 7.3V 3.1% |
| 200 ft | 2.0V 0.8% | 2.9V 1.2% | 3.9V 1.6% | 4.9V 2.0% | 5.9V 2.5% | 7.8V 3.3% | 9.8V 4.1% |
| 250 ft | 2.5V 1.0% | 3.7V 1.5% | 4.9V 2.0% | 6.1V 2.5% | 7.3V 3.1% | 9.8V 4.1% | 12.3V 5.1% |
| 300 ft | 2.9V 1.2% | 4.4V 1.8% | 5.9V 2.5% | 7.3V 3.1% | 8.8V 3.7% | 11.8V 4.9% | 14.7V 6.1% |
| 400 ft | 3.9V 1.6% | 5.9V 2.5% | 7.8V 3.3% | 9.8V 4.1% | 11.8V 4.9% | 15.7V 6.5% | 19.6V 8.2% |
| 500 ft | 4.9V 2.0% | 7.3V 3.1% | 9.8V 4.1% | 12.3V 5.1% | 14.7V 6.1% | 19.6V 8.2% | 24.5V 10.2% |
2 AWG Voltage Drop at 240V
Voltage drop values for 2 AWG copper conductor (0.194 ohms/kft) at 240 volts, single 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% | 0.4V 0.2% | 0.5V 0.2% | 0.6V 0.2% | 0.8V 0.3% | 1.0V 0.4% |
| 50 ft | 0.4V 0.2% | 0.6V 0.2% | 0.8V 0.3% | 1.0V 0.4% | 1.2V 0.5% | 1.6V 0.7% | 1.9V 0.8% |
| 75 ft | 0.6V 0.2% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 1.8V 0.7% | 2.3V 1.0% | 2.9V 1.2% |
| 100 ft | 0.8V 0.3% | 1.2V 0.5% | 1.6V 0.7% | 1.9V 0.8% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% |
| 125 ft | 1.0V 0.4% | 1.5V 0.6% | 1.9V 0.8% | 2.4V 1.0% | 2.9V 1.2% | 3.9V 1.6% | 4.8V 2.0% |
| 150 ft | 1.2V 0.5% | 1.8V 0.7% | 2.3V 1.0% | 2.9V 1.2% | 3.5V 1.5% | 4.7V 1.9% | 5.8V 2.4% |
| 200 ft | 1.6V 0.7% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% | 4.7V 1.9% | 6.2V 2.6% | 7.8V 3.2% |
| 250 ft | 1.9V 0.8% | 2.9V 1.2% | 3.9V 1.6% | 4.8V 2.0% | 5.8V 2.4% | 7.8V 3.2% | 9.7V 4.0% |
| 300 ft | 2.3V 1.0% | 3.5V 1.5% | 4.7V 1.9% | 5.8V 2.4% | 7.0V 2.9% | 9.3V 3.9% | 11.6V 4.8% |
| 400 ft | 3.1V 1.3% | 4.7V 1.9% | 6.2V 2.6% | 7.8V 3.2% | 9.3V 3.9% | 12.4V 5.2% | 15.5V 6.5% |
| 500 ft | 3.9V 1.6% | 5.8V 2.4% | 7.8V 3.2% | 9.7V 4.0% | 11.6V 4.8% | 15.5V 6.5% | 19.4V 8.1% |
1 AWG Voltage Drop at 240V
Voltage drop values for 1 AWG copper conductor (0.154 ohms/kft) at 240 volts, single 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% | 0.4V 0.2% | 0.5V 0.2% | 0.6V 0.3% | 0.8V 0.3% |
| 50 ft | 0.3V 0.1% | 0.5V 0.2% | 0.6V 0.3% | 0.8V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% |
| 75 ft | 0.5V 0.2% | 0.7V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.4V 0.6% | 1.9V 0.8% | 2.3V 1.0% |
| 100 ft | 0.6V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 1.9V 0.8% | 2.5V 1.0% | 3.1V 1.3% |
| 125 ft | 0.8V 0.3% | 1.2V 0.5% | 1.5V 0.6% | 1.9V 0.8% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% |
| 150 ft | 0.9V 0.4% | 1.4V 0.6% | 1.9V 0.8% | 2.3V 1.0% | 2.8V 1.2% | 3.7V 1.5% | 4.6V 1.9% |
| 200 ft | 1.2V 0.5% | 1.9V 0.8% | 2.5V 1.0% | 3.1V 1.3% | 3.7V 1.5% | 4.9V 2.0% | 6.2V 2.6% |
| 250 ft | 1.5V 0.6% | 2.3V 1.0% | 3.1V 1.3% | 3.9V 1.6% | 4.6V 1.9% | 6.2V 2.6% | 7.7V 3.2% |
| 300 ft | 1.9V 0.8% | 2.8V 1.2% | 3.7V 1.5% | 4.6V 1.9% | 5.5V 2.3% | 7.4V 3.1% | 9.2V 3.9% |
| 400 ft | 2.5V 1.0% | 3.7V 1.5% | 4.9V 2.0% | 6.2V 2.6% | 7.4V 3.1% | 9.9V 4.1% | 12.3V 5.1% |
| 500 ft | 3.1V 1.3% | 4.6V 1.9% | 6.2V 2.6% | 7.7V 3.2% | 9.2V 3.9% | 12.3V 5.1% | 15.4V 6.4% |
1/0 AWG Voltage Drop at 240V
Voltage drop values for 1/0 AWG copper conductor (0.122 ohms/kft) at 240 volts, single 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% | 0.4V 0.1% | 0.5V 0.2% | 0.6V 0.3% |
| 50 ft | 0.2V 0.1% | 0.4V 0.1% | 0.5V 0.2% | 0.6V 0.3% | 0.7V 0.3% | 1.0V 0.4% | 1.2V 0.5% |
| 75 ft | 0.4V 0.1% | 0.6V 0.2% | 0.7V 0.3% | 0.9V 0.4% | 1.1V 0.5% | 1.5V 0.6% | 1.8V 0.8% |
| 100 ft | 0.5V 0.2% | 0.7V 0.3% | 1.0V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 1.9V 0.8% | 2.4V 1.0% |
| 125 ft | 0.6V 0.3% | 0.9V 0.4% | 1.2V 0.5% | 1.5V 0.6% | 1.8V 0.8% | 2.4V 1.0% | 3.0V 1.3% |
| 150 ft | 0.7V 0.3% | 1.1V 0.5% | 1.5V 0.6% | 1.8V 0.8% | 2.2V 0.9% | 2.9V 1.2% | 3.7V 1.5% |
| 200 ft | 1.0V 0.4% | 1.5V 0.6% | 1.9V 0.8% | 2.4V 1.0% | 2.9V 1.2% | 3.9V 1.6% | 4.9V 2.0% |
| 250 ft | 1.2V 0.5% | 1.8V 0.8% | 2.4V 1.0% | 3.0V 1.3% | 3.7V 1.5% | 4.9V 2.0% | 6.1V 2.5% |
| 300 ft | 1.5V 0.6% | 2.2V 0.9% | 2.9V 1.2% | 3.7V 1.5% | 4.4V 1.8% | 5.9V 2.4% | 7.3V 3.0% |
| 400 ft | 1.9V 0.8% | 2.9V 1.2% | 3.9V 1.6% | 4.9V 2.0% | 5.9V 2.4% | 7.8V 3.3% | 9.8V 4.1% |
| 500 ft | 2.4V 1.0% | 3.7V 1.5% | 4.9V 2.0% | 6.1V 2.5% | 7.3V 3.0% | 9.8V 4.1% | 12.2V 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.
Tools and Training for Electricians
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