WireMath

Home › Wire size by amps › 300 amp › 75 ft

Wire size for 300 amps at 75 feet

Advertisement

300 A at 75 ft one-way

VoltageConductorMinimum sizeVoltage drop
120 VCopper350 kcmil1.65 V (1.38%)
120 VAluminum500 kcmil1.91 V (1.59%)
240 VCopper350 kcmil1.65 V (0.69%)
240 VAluminum500 kcmil1.91 V (0.80%)

Smallest size meeting NEC 75 °C ampacity (with 240.4(D) limits) and ≤3% drop at the full 300 A. Use 125% sizing for continuous loads; apply derating for more than 3 current-carrying conductors or high ambient temperature.

Adjust the numbers

FAQ

What size wire for 300 amps at 75 feet?

At 240 V: 350 kcmil copper keeps voltage drop under 3%. See the table for 120 V and aluminum.

Same current, other distances

Advertisement
XFacebookRedditWhatsAppLinkedIn

Free calculator by WireMath

Advertisement