Home › Wire size by amps › 100 amp › 25 ft

Wire size for 100 amps at 25 feet

100 A at 25 ft one-way

Voltage	Conductor	Minimum size	Voltage drop
120 V	Copper	3 AWG	1.23 V (1.02%)
120 V	Aluminum	1 AWG	1.26 V (1.05%)
240 V	Copper	3 AWG	1.23 V (0.51%)
240 V	Aluminum	1 AWG	1.26 V (0.53%)

Smallest size meeting NEC 75 °C ampacity (with 240.4(D) limits) and ≤3% drop at the full 100 A. Use 125% sizing for continuous loads; apply derating for more than 3 current-carrying conductors or high ambient temperature.

Adjust the numbers

Load current (amps)

One-way length (feet)

Voltage

Conductor

Max voltage drop (%)

Continuous load?

FAQ

What size wire for 100 amps at 25 feet?

At 240 V: 3 AWG copper keeps voltage drop under 3%. See the table for 120 V and aluminum.

Same current, other distances

X Facebook Reddit WhatsApp LinkedIn

Embed this free calculator on your site (copy & paste):

<iframe src="https://wiremath.pages.dev/wire-size/100-amp-25-feet/?embed=1" width="100%" height="640" style="border:1px solid #ddd;border-radius:12px" loading="lazy" title="WireMath calculator"></iframe><p style="font-size:13px">Calculator by <a href="https://wiremath.pages.dev/wire-size/100-amp-25-feet/">WireMath</a></p>

Free calculator by WireMath