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Wire Loss Table for 12 and 24 Volt Systems

Wire Loss Tables for Wind Turbines & Solar Panels

Use the wire loss tables below to determine the maximum distance one-way in feet of various gauges of two-conductor copper wire from the power source to load for 2% voltage drop in 12-volt and 24-volt system wiring. You can go twice the distance where a 4% loss is acceptable. Do not exceed the 2% drop for wire between PV modules (solar panels) and batteries. A 4% to 5% loss is acceptable between batteries and lighting circuits in most cases.

Note that if you change an array from 12 volts to 24 volts and the wattage remains the same, then the current is cut in half. This allows you to go 4 times as far with the same wire gauge with the 24-volt array as you could with the 12-volt array.

 

 

Wire Loss Table - 12 Volt Systems

Wire Size
Amps
#14
#12
#10
#8
#6
#4
#2
1/0
2/0
4/0
12 Volt System - 2% Voltage Drop
1 45 70 115 180 290 456 720      
2 22.5 35 57.5 90 145 228 360 580 720 1060
4 10 17.5 27.5 45 72.5 114 180 290 360 580
6 7.5 12 17.5 30 47.5 75 120 193 243 380
8 5.5 8.5 15 22.5 35.5 57 90 145 180 290
10 4.5 7 12 18 28.5 45.5 72.5 115 145 230
15 3 4.5 7 12 19 30 48 76.5 96 150
20 2 3.5 5.5 9 14.5 22.5 36 57.5 72.5 116
25 1.8 2.8 4.5 7 11.5 18 4829 46 58 92
30 1.5 2.4 3.5 6 9.5 15 24 38.5 48.5 77
40     2.8 4.5 7 11.5 18 29 36 56
50     2.3 3.6 5.5 9 14.5 23 29 46
100         2.9 4.6 7.2 11.5 14.5 23
150             4.8 7.7 9.7 15
200             3.6 5.8 7.3 11

 

Wire Loss Table - 24 Volt Systems

Wire Size
Amps #14 #12 #10 #8 #6 #4 #2 1/0 2/0 4/0
24 Volt System - 2% Voltage Drop
1 90 140 230 360 580 912 1440      
2 45 70 115 180 290 456 720 1160 1440 2120
4 20 35 55 90 145 228 360 580 720 1160
6 15 24 35 60 95 150 240 386 486 760
8 11 17 30 45 71 114 180 290 360 580
10 9 14 24 36 57 91 145 230 290 460
15 6 9 14 24 38 60 96 153 192 300
20 4 7 11 18 29 45 72 115 145 232
25 3.6 5.6 9 14 23 36 58 92 116 184
30 3 4.8 7 12 19 30 48 77 97 154
40     5.6 9 14 23 36 58 72 112
50     4.6 7.2 11 18 29 46 58 92
100         5.8 9.2 14.4 23 29 46
150             9.6 15.4 19.4 30
200             7.2 11.6 14.6 22