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

10 Amp Wire Size at 80 Feet (240V Three-Phase (US Industrial Delta))

Complete conductor sizing, Ohm's law voltage drop, $I^2R$ line power loss, and circuit breaker specification for a 10 A load over a 80 ft (24.4 m) one-way run.

Copper Wire (≤3% Drop)14 AWG2.08 mm² · Drop: 1.81%
Aluminum Wire (≤3% Drop)14 AWGDrop: 7.17V (2.99%)
Voltage at Load End235.7 VLoss: 4.35 V (75.3 W)
Power & Breaker (125%)4.16 kW13A Breaker Recommended

All AWG & kcmil Wire Gauges for 10 Amps at 80 Feet (240V)

Wire GaugeMetric AreaNEC 75°C Cu Ampacity Copper Voltage DropLoad VoltageAluminum DropLine Loss ($I^2R$)NEC Status
14 AWG2.08 mm²15 A4.35 V (1.81%)235.7 V7.17 V (2.99%)75.3 W✓ PASS (≤3%)
12 AWG3.31 mm²20 A2.73 V (1.14%)237.3 V4.5 V (1.88%)47.3 W✓ PASS (≤3%)
10 AWG5.26 mm²30 A1.72 V (0.72%)238.3 V2.83 V (1.18%)29.8 W✓ PASS (≤3%)
8 AWG8.37 mm²50 A1.08 V (0.45%)238.9 V1.78 V (0.74%)18.7 W✓ PASS (≤3%)
6 AWG13.3 mm²65 A0.68 V (0.28%)239.3 V1.12 V (0.47%)11.8 W✓ PASS (≤3%)
4 AWG21.15 mm²85 A0.43 V (0.18%)239.6 V0.7 V (0.29%)7.4 W✓ PASS (≤3%)
3 AWG26.67 mm²100 A0.34 V (0.14%)239.7 V0.56 V (0.23%)5.9 W✓ PASS (≤3%)
2 AWG33.62 mm²115 A0.27 V (0.11%)239.7 V0.44 V (0.18%)4.7 W✓ PASS (≤3%)
1 AWG42.41 mm²130 A0.21 V (0.09%)239.8 V0.35 V (0.15%)3.7 W✓ PASS (≤3%)
1/0 AWG53.49 mm²150 A0.17 V (0.07%)239.8 V0.28 V (0.12%)2.9 W✓ PASS (≤3%)
2/0 AWG67.43 mm²175 A0.13 V (0.06%)239.9 V0.22 V (0.09%)2.3 W✓ PASS (≤3%)
3/0 AWG85.01 mm²200 A0.11 V (0.04%)239.9 V0.18 V (0.07%)1.8 W✓ PASS (≤3%)
4/0 AWG107.2 mm²230 A0.08 V (0.04%)239.9 V0.14 V (0.06%)1.5 W✓ PASS (≤3%)
250 kcmil126.7 mm²255 A0.07 V (0.03%)239.9 V0.12 V (0.05%)1.2 W✓ PASS (≤3%)
300 kcmil152.0 mm²285 A0.06 V (0.02%)239.9 V0.1 V (0.04%)1.0 W✓ PASS (≤3%)
350 kcmil177.3 mm²310 A0.05 V (0.02%)239.9 V0.08 V (0.04%)0.9 W✓ PASS (≤3%)
400 kcmil202.7 mm²335 A0.04 V (0.02%)240.0 V0.07 V (0.03%)0.8 W✓ PASS (≤3%)
500 kcmil253.4 mm²380 A0.04 V (0.01%)240.0 V0.06 V (0.02%)0.6 W✓ PASS (≤3%)
600 kcmil304.0 mm²420 A0.03 V (0.01%)240.0 V0.05 V (0.02%)0.5 W✓ PASS (≤3%)
750 kcmil380.0 mm²475 A0.02 V (0.01%)240.0 V0.04 V (0.02%)0.4 W✓ PASS (≤3%)
1000 kcmil506.7 mm²545 A0.02 V (0.01%)240.0 V0.03 V (0.01%)0.3 W✓ PASS (≤3%)

Frequently Asked Engineering Questions

What size copper wire do I need for 10 amps at 80 feet (240V)?

To stay within the NEC recommended 3% maximum voltage drop for a 10A load over 80 feet one-way at 240V (3-Phase), you need 14 AWG copper wire. This produces a voltage drop of 4.35V (1.81%) and delivers 235.7V at the load.

What size aluminum wire is required for 10 amps at 80 feet?

Using aluminum conductors (75°C rating), you should use 14 AWG to maintain voltage drop at 7.17V (2.99%).

What breaker size is needed for a 10A continuous load?

Under NEC 210.20(A), continuous loads require a circuit breaker rated at 125% of the continuous current (10A × 1.25 = 12.5A), which corresponds to a standard 13A circuit breaker.