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🇺🇸 NEC NFPA 70 · Table 310.16 (75°C) · Voltage Drop Analysis

375 Amp Wire Size at 30 Feet (240V Split-Phase (US Dryer / EV / Subpanel))

Complete conductor sizing, Ohm's law voltage drop, $I^2R$ line power loss, and circuit breaker specification for a 375 A load over a 30 ft (9.1 m) one-way run.

Copper Wire (≤3% Drop)500 kcmil253.4 mm² · Drop: 0.24%
Aluminum Wire (≤3% Drop)750 kcmilDrop: 0.64V (0.27%)
Voltage at Load End239.4 VLoss: 0.58 V (217.2 W)
Power & Breaker (125%)90.0 kW500A Breaker Recommended

All AWG & kcmil Wire Gauges for 375 Amps at 30 Feet (240V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A70.56 V (29.4%)169.4 V116.39 V (48.5%)26459.4 WDrop/Amp High
12 AWG3.31 mm²20 A44.34 V (18.47%)195.7 V73.14 V (30.47%)16627.0 WDrop/Amp High
10 AWG5.26 mm²30 A27.9 V (11.63%)212.1 V46.02 V (19.18%)10463.0 WDrop/Amp High
8 AWG8.37 mm²50 A17.53 V (7.31%)222.5 V28.92 V (12.05%)6575.3 WDrop/Amp High
6 AWG13.3 mm²65 A11.03 V (4.6%)229.0 V18.2 V (7.58%)4138.0 WDrop/Amp High
4 AWG21.15 mm²85 A6.94 V (2.89%)233.1 V11.45 V (4.77%)2602.1 WDrop/Amp High
3 AWG26.67 mm²100 A5.5 V (2.29%)234.5 V9.08 V (3.78%)2063.6 WDrop/Amp High
2 AWG33.62 mm²115 A4.37 V (1.82%)235.6 V7.2 V (3.0%)1637.0 WDrop/Amp High
1 AWG42.41 mm²130 A3.46 V (1.44%)236.5 V5.71 V (2.38%)1297.7 WDrop/Amp High
1/0 AWG53.49 mm²150 A2.74 V (1.14%)237.3 V4.53 V (1.89%)1028.9 WDrop/Amp High
2/0 AWG67.43 mm²175 A2.18 V (0.91%)237.8 V3.59 V (1.5%)816.2 WDrop/Amp High
3/0 AWG85.01 mm²200 A1.73 V (0.72%)238.3 V2.85 V (1.19%)647.4 WDrop/Amp High
4/0 AWG107.2 mm²230 A1.37 V (0.57%)238.6 V2.26 V (0.94%)513.4 WDrop/Amp High
250 kcmil126.7 mm²255 A1.16 V (0.48%)238.8 V1.91 V (0.8%)434.4 WDrop/Amp High
300 kcmil152.0 mm²285 A0.97 V (0.4%)239.0 V1.59 V (0.66%)362.1 WDrop/Amp High
350 kcmil177.3 mm²310 A0.83 V (0.34%)239.2 V1.37 V (0.57%)310.4 WDrop/Amp High
400 kcmil202.7 mm²335 A0.72 V (0.3%)239.3 V1.19 V (0.5%)271.5 WDrop/Amp High
500 kcmil253.4 mm²380 A0.58 V (0.24%)239.4 V0.96 V (0.4%)217.2 W✓ PASS (≤3%)
600 kcmil304.0 mm²420 A0.48 V (0.2%)239.5 V0.8 V (0.33%)181.0 W✓ PASS (≤3%)
750 kcmil380.0 mm²475 A0.39 V (0.16%)239.6 V0.64 V (0.27%)144.8 W✓ PASS (≤3%)
1000 kcmil506.7 mm²545 A0.29 V (0.12%)239.7 V0.48 V (0.2%)108.6 W✓ PASS (≤3%)

Frequently Asked Engineering Questions

What size copper wire do I need for 375 amps at 30 feet (240V)?

To stay within the NEC recommended 3% maximum voltage drop for a 375A load over 30 feet one-way at 240V (1-Phase), you need 500 kcmil copper wire. This produces a voltage drop of 0.58V (0.24%) and delivers 239.4V at the load.

What size aluminum wire is required for 375 amps at 30 feet?

Using aluminum conductors (75°C rating), you should use 750 kcmil to maintain voltage drop at 0.64V (0.27%).

What breaker size is needed for a 375A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (375A × 1.25 = 468.8A), which corresponds to a standard 500A circuit breaker.