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

450 Amp Wire Size at 225 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 450 A load over a 225 ft (68.6 m) one-way run.

Copper Wire (≤3% Drop)750 kcmil380.0 mm² · Drop: 1.45%
Aluminum Wire (≤3% Drop)1000 kcmilDrop: 4.3V (1.79%)
Voltage at Load End236.5 VLoss: 3.48 V (1564.2 W)
Power & Breaker (125%)108.0 kW600A Breaker Recommended

All AWG & kcmil Wire Gauges for 450 Amps at 225 Feet (240V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A635.02 V (264.59%)0.0 V1047.49 V (436.46%)285761.0 WDrop/Amp High
12 AWG3.31 mm²20 A399.05 V (166.27%)0.0 V658.24 V (274.27%)179571.9 WDrop/Amp High
10 AWG5.26 mm²30 A251.11 V (104.63%)0.0 V414.22 V (172.59%)113000.5 WDrop/Amp High
8 AWG8.37 mm²50 A157.81 V (65.75%)82.2 V260.31 V (108.46%)71013.5 WDrop/Amp High
6 AWG13.3 mm²65 A99.31 V (41.38%)140.7 V163.82 V (68.26%)44690.4 WDrop/Amp High
4 AWG21.15 mm²85 A62.45 V (26.02%)177.5 V103.02 V (42.92%)28103.2 WDrop/Amp High
3 AWG26.67 mm²100 A49.53 V (20.64%)190.5 V81.69 V (34.04%)22286.6 WDrop/Amp High
2 AWG33.62 mm²115 A39.29 V (16.37%)200.7 V64.81 V (27.0%)17679.4 WDrop/Amp High
1 AWG42.41 mm²130 A31.14 V (12.98%)208.9 V51.37 V (21.41%)14015.2 WDrop/Amp High
1/0 AWG53.49 mm²150 A24.69 V (10.29%)215.3 V40.73 V (16.97%)11112.0 WDrop/Amp High
2/0 AWG67.43 mm²175 A19.59 V (8.16%)220.4 V32.31 V (13.46%)8814.8 WDrop/Amp High
3/0 AWG85.01 mm²200 A15.54 V (6.47%)224.5 V25.63 V (10.68%)6991.9 WDrop/Amp High
4/0 AWG107.2 mm²230 A12.32 V (5.13%)227.7 V20.32 V (8.47%)5544.6 WDrop/Amp High
250 kcmil126.7 mm²255 A10.43 V (4.34%)229.6 V17.2 V (7.17%)4691.3 WDrop/Amp High
300 kcmil152.0 mm²285 A8.69 V (3.62%)231.3 V14.33 V (5.97%)3910.4 WDrop/Amp High
350 kcmil177.3 mm²310 A7.45 V (3.1%)232.6 V12.29 V (5.12%)3352.4 WDrop/Amp High
400 kcmil202.7 mm²335 A6.52 V (2.72%)233.5 V10.75 V (4.48%)2932.3 WDrop/Amp High
500 kcmil253.4 mm²380 A5.21 V (2.17%)234.8 V8.6 V (3.58%)2345.6 WDrop/Amp High
600 kcmil304.0 mm²420 A4.34 V (1.81%)235.7 V7.17 V (2.99%)1955.2 WDrop/Amp High
750 kcmil380.0 mm²475 A3.48 V (1.45%)236.5 V5.73 V (2.39%)1564.2 W✓ PASS (≤3%)
1000 kcmil506.7 mm²545 A2.61 V (1.09%)237.4 V4.3 V (1.79%)1173.0 W✓ PASS (≤3%)

Frequently Asked Engineering Questions

What size copper wire do I need for 450 amps at 225 feet (240V)?

To stay within the NEC recommended 3% maximum voltage drop for a 450A load over 225 feet one-way at 240V (1-Phase), you need 750 kcmil copper wire. This produces a voltage drop of 3.48V (1.45%) and delivers 236.5V at the load.

What size aluminum wire is required for 450 amps at 225 feet?

Using aluminum conductors (75°C rating), you should use 1000 kcmil to maintain voltage drop at 4.3V (1.79%).

What breaker size is needed for a 450A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (450A × 1.25 = 562.5A), which corresponds to a standard 600A circuit breaker.