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 90140 230 360 580 912 1440


    2 4570115180 290456 720 1160 14402120
    4 20355590145228360580 720 1160
    6 1524356095150240386 486 760
    8 1117304571114180290 360 580
    10 9 1424365791145230 290 460
    15 6 91424386096153 192300
    20 471118294572115 145232
    253.65.691423365892116184
    30 34.87121930487797154
    40

    5.691423365872112
    50

    4.67.2111829465892
    100



    5.89.214.4232946
    150





    9.615.419.430
    200





    7.211.614.622