Voltage drop scenario
At 240 V single-phase, copper 6 AWG keeps a 60 amps load at about 2.46% drop over 100 feet — within the 3% design target used here. Adjust material, voltage, or phase below.
Voltage drop
—Enter a run to estimate voltage drop.
| Voltage drop | — |
|---|---|
| Percent drop | — |
| Voltage at load | — |
| Resistance used | — |
At 240 V single-phase over 100 feet, a 60 amps load needs copper 6 AWG to stay near 2.46% — inside the 3% design target used for this comparison. For comparison, copper 12 AWG would drop about 23.16 V (9.65%) on the same run.
This is a voltage-drop estimate only. The conductor must also meet ampacity, temperature derating, and overcurrent rules — use the larger of the voltage-drop size and the ampacity size. Aluminum of the same size drops more, so it usually needs to go up one or two sizes. Always confirm with a licensed electrician and your local code (AHJ).
Sized for voltage drop using NEC Ch.9 Table 8 DC resistance. The 3% figure is a common design target from informational guidance, not a substitute for a code review.
A 60 A planning case can describe large HVAC equipment, a feeder, shop equipment, or a circuit whose breaker is 60 A. A common EV example is different: a 60 A circuit often supports a 48 A continuous charger, so the calculator should normally receive the design load rather than the breaker number.
Run both the expected operating current and any relevant equipment maximum. That reveals whether voltage drop is driven by normal use or only by a rating printed on the overcurrent device. The final conductor still has to satisfy equipment instructions and code rules that this voltage-drop calculation does not model.
| One-way distance | Suggested copper size | Calculated drop |
|---|---|---|
| 50 ft | 8 AWG | 1.91% |
| 100 ft | 6 AWG | 2.46% |
| 150 ft | 4 AWG | 2.31% |
| 200 ft | 3 AWG | 2.45% |
For voltage drop at 240 V single-phase, copper 6 AWG keeps a 60 amps load near 2.46% over 100 feet, meeting the 3% design target used on this page. Ampacity, derating, equipment instructions, and local code may require a different size — confirm with a licensed electrician.
On a baseline copper 12 AWG at 240 V single-phase, 60 amps over 100 feet drops about 23.16 V (9.65%). Larger conductors drop less; the calculator shows the exact figure for any size.
No. This page sizes for voltage drop only, using NEC Chapter 9 Table 8 DC resistance. The conductor must also satisfy ampacity, temperature derating, and overcurrent-protection rules. Use the larger of the voltage-drop size and the ampacity size, and verify with your local code (AHJ).
Source links and page assumptions reviewed .
Estimate only, based on NEC Chapter 9 Table 8 DC resistance. Not a substitute for a licensed electrician or your local code (AHJ). Voltage-drop sizing does not replace ampacity, temperature derating, power factor, or continuous-load checks. Verify against the current NEC and local code before wiring. Based on NEC Ch.9 Table 8.