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

650 Amp Wire Size at 150 Feet (480V Three-Phase (US Heavy Industrial))

Complete conductor sizing, Ohm's law voltage drop, $I^2R$ line power loss, and circuit breaker specification for a 650 A load over a 150 ft (45.7 m) one-way run.

Copper Wire (≤3% Drop)2× 1000 kcmil (Parallel)506.7 mm² · Drop: 0.23%
Aluminum Wire (≤3% Drop)1000 kcmilDrop: 3.59V (0.75%)
Voltage at Load End478.9 VLoss: 1.08 V (1223.8 W)
Power & Breaker (125%)540.4 kW1000A Breaker Recommended

All AWG & kcmil Wire Gauges for 650 Amps at 150 Feet (480V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A529.58 V (110.33%)0.0 V873.56 V (181.99%)596217.4 WDrop/Amp High
12 AWG3.31 mm²20 A332.79 V (69.33%)147.2 V548.94 V (114.36%)374662.3 WDrop/Amp High
10 AWG5.26 mm²30 A209.42 V (43.63%)270.6 V345.44 V (71.97%)235766.6 WDrop/Amp High
8 AWG8.37 mm²50 A131.6 V (27.42%)348.4 V217.08 V (45.23%)148163.9 WDrop/Amp High
6 AWG13.3 mm²65 A82.82 V (17.25%)397.2 V136.62 V (28.46%)93243.0 WDrop/Amp High
4 AWG21.15 mm²85 A52.08 V (10.85%)427.9 V85.91 V (17.9%)58635.1 WDrop/Amp High
3 AWG26.67 mm²100 A41.3 V (8.6%)438.7 V68.13 V (14.19%)46499.1 WDrop/Amp High
2 AWG33.62 mm²115 A32.76 V (6.83%)447.2 V54.05 V (11.26%)36886.7 WDrop/Amp High
1 AWG42.41 mm²130 A25.97 V (5.41%)454.0 V42.84 V (8.93%)29241.5 WDrop/Amp High
1/0 AWG53.49 mm²150 A20.59 V (4.29%)459.4 V33.97 V (7.08%)23184.4 WDrop/Amp High
2/0 AWG67.43 mm²175 A16.34 V (3.4%)463.7 V26.95 V (5.61%)18391.4 WDrop/Amp High
3/0 AWG85.01 mm²200 A12.96 V (2.7%)467.0 V21.37 V (4.45%)14588.1 WDrop/Amp High
4/0 AWG107.2 mm²230 A10.28 V (2.14%)469.7 V16.95 V (3.53%)11568.4 WDrop/Amp High
250 kcmil126.7 mm²255 A8.69 V (1.81%)471.3 V14.34 V (2.99%)9787.9 WDrop/Amp High
300 kcmil152.0 mm²285 A7.25 V (1.51%)472.8 V11.95 V (2.49%)8158.8 WDrop/Amp High
350 kcmil177.3 mm²310 A6.21 V (1.29%)473.8 V10.25 V (2.14%)6994.5 WDrop/Amp High
400 kcmil202.7 mm²335 A5.43 V (1.13%)474.6 V8.96 V (1.87%)6118.1 WDrop/Amp High
500 kcmil253.4 mm²380 A4.35 V (0.91%)475.7 V7.17 V (1.49%)4894.0 WDrop/Amp High
600 kcmil304.0 mm²420 A3.62 V (0.75%)476.4 V5.98 V (1.25%)4079.4 WDrop/Amp High
750 kcmil380.0 mm²475 A2.9 V (0.6%)477.1 V4.78 V (1.0%)3263.5 WDrop/Amp High
1000 kcmil506.7 mm²545 A2.17 V (0.45%)477.8 V3.59 V (0.75%)2447.5 WDrop/Amp High

Frequently Asked Engineering Questions

What size copper wire do I need for 650 amps at 150 feet (480V)?

To stay within the NEC recommended 3% maximum voltage drop for a 650A load over 150 feet one-way at 480V (3-Phase), you need 2× 1000 kcmil (Parallel) copper wire. This produces a voltage drop of 1.08V (0.23%) and delivers 478.9V at the load.

What size aluminum wire is required for 650 amps at 150 feet?

Using aluminum conductors (75°C rating), you should use 1000 kcmil to maintain voltage drop at 3.59V (0.75%).

What breaker size is needed for a 650A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (650A × 1.25 = 812.5A), which corresponds to a standard 1000A circuit breaker.