National Electrical Code (NEC 310.16)90 Verified Distance & Load Combinations
Electrical Wire Sizing & Voltage Drop Directory
Direct engineering factsheets for electricians, solar technicians, and contractors. Select your target circuit amperage and distance to view the exact required copper/aluminum gauge, conduit fill limits, and continuous load capacities.
15 Amp Breaker Circuit Sizing
Max 80% continuous draw: 12.0A · Standard Cu: #14 AWG50 ft Run (120V)
Copper:#12 AWG
Voltage Drop:3.84%
Conduit:1/2"
100 ft Run (120V)
Copper:#8 AWG
Voltage Drop:7.67%
Conduit:3/4"
150 ft Run (120V)
Copper:#8 AWG
Voltage Drop:11.51%
Conduit:3/4"
200 ft Run (120V)
Copper:#6 AWG
Voltage Drop:15.35%
Conduit:3/4"
250 ft Run (120V)
Copper:#4 AWG
Voltage Drop:19.19%
Conduit:1"
300 ft Run (120V)
Copper:#4 AWG
Voltage Drop:23.03%
Conduit:1"
50 ft Run (240V)
Copper:#14 AWG
Voltage Drop:1.92%
Conduit:1/2"
100 ft Run (240V)
Copper:#12 AWG
Voltage Drop:3.84%
Conduit:1/2"
150 ft Run (240V)
Copper:#10 AWG
Voltage Drop:5.76%
Conduit:1/2"
200 ft Run (240V)
Copper:#8 AWG
Voltage Drop:7.67%
Conduit:3/4"
250 ft Run (240V)
Copper:#8 AWG
Voltage Drop:9.59%
Conduit:3/4"
300 ft Run (240V)
Copper:#8 AWG
Voltage Drop:11.51%
Conduit:3/4"
20 Amp Breaker Circuit Sizing
Max 80% continuous draw: 16.0A · Standard Cu: #12 AWG50 ft Run (120V)
Copper:#10 AWG
Voltage Drop:3.22%
Conduit:1/2"
100 ft Run (120V)
Copper:#8 AWG
Voltage Drop:6.43%
Conduit:3/4"
150 ft Run (120V)
Copper:#6 AWG
Voltage Drop:9.65%
Conduit:3/4"
200 ft Run (120V)
Copper:#4 AWG
Voltage Drop:12.87%
Conduit:1"
250 ft Run (120V)
Copper:#4 AWG
Voltage Drop:16.08%
Conduit:1"
300 ft Run (120V)
Copper:#3 AWG
Voltage Drop:19.3%
Conduit:1"
50 ft Run (240V)
Copper:#12 AWG
Voltage Drop:1.61%
Conduit:1/2"
100 ft Run (240V)
Copper:#10 AWG
Voltage Drop:3.22%
Conduit:1/2"
150 ft Run (240V)
Copper:#8 AWG
Voltage Drop:4.82%
Conduit:3/4"
200 ft Run (240V)
Copper:#8 AWG
Voltage Drop:6.43%
Conduit:3/4"
250 ft Run (240V)
Copper:#6 AWG
Voltage Drop:8.04%
Conduit:3/4"
300 ft Run (240V)
Copper:#6 AWG
Voltage Drop:9.65%
Conduit:3/4"
30 Amp Breaker Circuit Sizing
Max 80% continuous draw: 24.0A · Standard Cu: #10 AWG50 ft Run (120V)
Copper:#8 AWG
Voltage Drop:3.02%
Conduit:3/4"
100 ft Run (120V)
Copper:#6 AWG
Voltage Drop:6.05%
Conduit:3/4"
150 ft Run (120V)
Copper:#4 AWG
Voltage Drop:9.08%
Conduit:1"
200 ft Run (120V)
Copper:#3 AWG
Voltage Drop:12.1%
Conduit:1"
250 ft Run (120V)
Copper:#2 AWG
Voltage Drop:15.13%
Conduit:1"
300 ft Run (120V)
Copper:#2 AWG
Voltage Drop:18.15%
Conduit:1"
50 ft Run (240V)
Copper:#10 AWG
Voltage Drop:1.51%
Conduit:1/2"
100 ft Run (240V)
Copper:#8 AWG
Voltage Drop:3.02%
Conduit:3/4"
150 ft Run (240V)
Copper:#8 AWG
Voltage Drop:4.54%
Conduit:3/4"
200 ft Run (240V)
Copper:#6 AWG
Voltage Drop:6.05%
Conduit:3/4"
250 ft Run (240V)
Copper:#4 AWG
Voltage Drop:7.56%
Conduit:1"
300 ft Run (240V)
Copper:#4 AWG
Voltage Drop:9.08%
Conduit:1"
40 Amp Breaker Circuit Sizing
Max 80% continuous draw: 32.0A · Standard Cu: #8 AWG50 ft Run (240V)
Copper:#8 AWG
Voltage Drop:1.27%
Conduit:3/4"
100 ft Run (240V)
Copper:#8 AWG
Voltage Drop:2.55%
Conduit:3/4"
150 ft Run (240V)
Copper:#6 AWG
Voltage Drop:3.82%
Conduit:3/4"
200 ft Run (240V)
Copper:#4 AWG
Voltage Drop:5.09%
Conduit:1"
250 ft Run (240V)
Copper:#4 AWG
Voltage Drop:6.37%
Conduit:1"
300 ft Run (240V)
Copper:#3 AWG
Voltage Drop:7.64%
Conduit:1"
50 Amp Breaker Circuit Sizing
Max 80% continuous draw: 40.0A · Standard Cu: #8 AWG50 ft Run (240V)
Copper:#8 AWG
Voltage Drop:1.59%
Conduit:3/4"
100 ft Run (240V)
Copper:#6 AWG
Voltage Drop:3.18%
Conduit:3/4"
150 ft Run (240V)
Copper:#4 AWG
Voltage Drop:4.78%
Conduit:1"
200 ft Run (240V)
Copper:#4 AWG
Voltage Drop:6.37%
Conduit:1"
250 ft Run (240V)
Copper:#3 AWG
Voltage Drop:7.96%
Conduit:1"
300 ft Run (240V)
Copper:#2 AWG
Voltage Drop:9.55%
Conduit:1"
60 Amp Breaker Circuit Sizing
Max 80% continuous draw: 48.0A · Standard Cu: #6 AWG50 ft Run (240V)
Copper:#6 AWG
Voltage Drop:1.23%
Conduit:3/4"
100 ft Run (240V)
Copper:#6 AWG
Voltage Drop:2.46%
Conduit:3/4"
150 ft Run (240V)
Copper:#4 AWG
Voltage Drop:3.68%
Conduit:1"
200 ft Run (240V)
Copper:#3 AWG
Voltage Drop:4.91%
Conduit:1"
250 ft Run (240V)
Copper:#2 AWG
Voltage Drop:6.14%
Conduit:1"
300 ft Run (240V)
Copper:#2 AWG
Voltage Drop:7.37%
Conduit:1"
70 Amp Breaker Circuit Sizing
Max 80% continuous draw: 56.0A · Standard Cu: #4 AWG50 ft Run (240V)
Copper:#4 AWG
Voltage Drop:0.9%
Conduit:1"
100 ft Run (240V)
Copper:#4 AWG
Voltage Drop:1.8%
Conduit:1"
150 ft Run (240V)
Copper:#4 AWG
Voltage Drop:2.7%
Conduit:1"
200 ft Run (240V)
Copper:#3 AWG
Voltage Drop:3.59%
Conduit:1"
250 ft Run (240V)
Copper:#2 AWG
Voltage Drop:4.49%
Conduit:1"
300 ft Run (240V)
Copper:#1 AWG
Voltage Drop:5.39%
Conduit:1-1/4"
80 Amp Breaker Circuit Sizing
Max 80% continuous draw: 64.0A · Standard Cu: #4 AWG50 ft Run (240V)
Copper:#4 AWG
Voltage Drop:1.03%
Conduit:1"
100 ft Run (240V)
Copper:#4 AWG
Voltage Drop:2.05%
Conduit:1"
150 ft Run (240V)
Copper:#3 AWG
Voltage Drop:3.08%
Conduit:1"
200 ft Run (240V)
Copper:#2 AWG
Voltage Drop:4.11%
Conduit:1"
250 ft Run (240V)
Copper:#1 AWG
Voltage Drop:5.13%
Conduit:1-1/4"
300 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:6.16%
Conduit:1-1/4"
100 Amp Breaker Circuit Sizing
Max 80% continuous draw: 80.0A · Standard Cu: #3 AWG50 ft Run (240V)
Copper:#3 AWG
Voltage Drop:1.02%
Conduit:1"
100 ft Run (240V)
Copper:#3 AWG
Voltage Drop:2.04%
Conduit:1"
150 ft Run (240V)
Copper:#2 AWG
Voltage Drop:3.06%
Conduit:1"
200 ft Run (240V)
Copper:#1 AWG
Voltage Drop:4.08%
Conduit:1-1/4"
250 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:5.1%
Conduit:1-1/4"
300 ft Run (240V)
Copper:2/0 AWG
Voltage Drop:6.13%
Conduit:1-1/2"
125 Amp Breaker Circuit Sizing
Max 80% continuous draw: 100.0A · Standard Cu: #1 AWG50 ft Run (240V)
Copper:#1 AWG
Voltage Drop:0.8%
Conduit:1-1/4"
100 ft Run (240V)
Copper:#1 AWG
Voltage Drop:1.6%
Conduit:1-1/4"
150 ft Run (240V)
Copper:#1 AWG
Voltage Drop:2.41%
Conduit:1-1/4"
200 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:3.21%
Conduit:1-1/4"
250 ft Run (240V)
Copper:2/0 AWG
Voltage Drop:4.01%
Conduit:1-1/2"
300 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:4.81%
Conduit:1-1/2"
150 Amp Breaker Circuit Sizing
Max 80% continuous draw: 120.0A · Standard Cu: 1/0 AWG50 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:0.76%
Conduit:1-1/4"
100 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:1.52%
Conduit:1-1/4"
150 ft Run (240V)
Copper:1/0 AWG
Voltage Drop:2.29%
Conduit:1-1/4"
200 ft Run (240V)
Copper:2/0 AWG
Voltage Drop:3.05%
Conduit:1-1/2"
250 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:3.81%
Conduit:1-1/2"
300 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:4.58%
Conduit:1-1/2"
200 Amp Breaker Circuit Sizing
Max 80% continuous draw: 160.0A · Standard Cu: 3/0 AWG50 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:0.64%
Conduit:1-1/2"
100 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:1.28%
Conduit:1-1/2"
150 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:1.92%
Conduit:1-1/2"
200 ft Run (240V)
Copper:3/0 AWG
Voltage Drop:2.55%
Conduit:1-1/2"
250 ft Run (240V)
Copper:4/0 AWG
Voltage Drop:3.19%
Conduit:2"
300 ft Run (240V)
Copper:250 kcmil
Voltage Drop:3.83%
Conduit:2"