Find the amperes or watts the circuit is expected to carry on the left and the distance the wiring must run at the top - follow the columns until they intersect - for example, a 12 volt circuit which is 15 feet long and carries 10 amperes should use at least 16 gauge wire.
WIRE GAUGE SELECTION TABLE |
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Circuit Amperes |
Circuit Watts |
Wire gauge (for length in feet) |
||||||||
6V |
12V |
6V |
12V |
3' |
5' |
7' |
10' |
15' |
20' |
25' |
0 to 2.5 |
0 to 5 |
15 |
30 |
18 |
18 |
18 |
18 |
18 |
18 |
18 |
3.0 |
6 |
18 |
36 |
18 |
18 |
18 |
18 |
18 |
18 |
16 |
3.5 |
7 |
21 |
42 |
18 |
18 |
18 |
18 |
18 |
18 |
16 |
4.0 |
8 |
24 |
48 |
18 |
18 |
18 |
18 |
18 |
16 |
16 |
5.0 |
10 |
30 |
60 |
18 |
18 |
18 |
18 |
16 |
16 |
16 |
5.5 |
11 |
33 |
66 |
18 |
18 |
18 |
18 |
16 |
16 |
14 |
6.0 |
12 |
36 |
72 |
18 |
18 |
18 |
18 |
16 |
16 |
14 |
7.5 |
15 |
45 |
90 |
18 |
18 |
18 |
18 |
14 |
14 |
12 |
9.0 |
18 |
54 |
108 |
18 |
18 |
16 |
16 |
14 |
14 |
12 |
10 |
20 |
60 |
120 |
18 |
18 |
16 |
16 |
14 |
12 |
10 |
11 |
22 |
66 |
132 |
18 |
18 |
16 |
16 |
12 |
12 |
10 |
12 |
24 |
72 |
144 |
18 |
18 |
16 |
16 |
12 |
12 |
10 |
15 |
30 |
90 |
180 |
18 |
16 |
16 |
14 |
10 |
10 |
10 |
20 |
40 |
120 |
240 |
18 |
16 |
14 |
12 |
10 |
10 |
8 |
25 |
50 |
150 |
300 |
16 |
14 |
12 |
12 |
10 |
10 |
8 |
50 |
100 |
300 |
600 |
12 |
12 |
10 |
10 |
6 |
6 |
4 |
75 |
150 |
450 |
900 |
10 |
10 |
8 |
8 |
4 |
4 |
2 |
100 |
200 |
600 |
1200 |
10 |
8 |
8 |
6 |
4 |
4 |
2 |