|
12 Volt Wiring Reference Guide
The size of the wire you're using must be large enough to carry the maximum current expected without undue voltage losses. All wire has a certain amount of resistance to the flow of current. This resistance causes a drop in the voltage from the source to the load. Voltage drops cause inefficiencies, especially in low voltage systems (12V or less).
The wire sizing guide below provides the minimum wire size needed to limit voltage drops to 5% at a given distance in a 12V system. If you want to limit your losses to 2% simply divide the distance by 2.5.
| AWG gauge |
Diameter Inches |
Diameter mm |
Ohms per 1000 ft |
Ohms per km |
Maximum amps for chassis wiring |
Maximum amps for power transmission |
| OOOO |
0.46 |
11.684 |
0.049 |
0.16072 |
380 |
302 |
| OOO |
0.4096 |
10.40384 |
0.0618 |
0.202704 |
328 |
239 |
| OO |
0.3648 |
9.26592 |
0.0779 |
0.255512 |
283 |
190 |
| 0 |
0.3249 |
8.25246 |
0.0983 |
0.322424 |
245 |
150 |
| 1 |
0.2893 |
7.34822 |
0.1239 |
0.406392 |
211 |
119 |
| 2 |
0.2576 |
6.54304 |
0.1563 |
0.512664 |
181 |
94 |
| 3 |
0.2294 |
5.82676 |
0.197 |
0.64616 |
158 |
75 |
| 4 |
0.2043 |
5.18922 |
0.2485 |
0.81508 |
135 |
60 |
| 5 |
0.1819 |
4.62026 |
0.3133 |
1.027624 |
118 |
47 |
| 6 |
0.162 |
4.1148 |
0.3951 |
1.295928 |
101 |
37 |
| 7 |
0.1443 |
3.66522 |
0.4982 |
1.634096 |
89 |
30 |
| 8 |
0.1285 |
3.2639 |
0.6282 |
2.060496 |
73 |
24 |
| 9 |
0.1144 |
2.90576 |
0.7921 |
2.598088 |
64 |
19 |
| 10 |
0.1019 |
2.58826 |
0.9989 |
3.276392 |
55 |
15 |
| 11 |
0.0907 |
2.30378 |
1.26 |
4.1328 |
47 |
12 |
| 12 |
0.0808 |
2.05232 |
1.588 |
5.20864 |
41 |
9.3 |
| 13 |
0.072 |
1.8288 |
2.003 |
6.56984 |
35 |
7.4 |
| 14 |
0.0641 |
1.62814 |
2.525 |
8.282 |
32 |
5.9 |
| 15 |
0.0571 |
1.45034 |
3.184 |
10.44352 |
28 |
4.7 |
| 16 |
0.0508 |
1.29032 |
4.016 |
13.17248 |
22 |
3.7 |
| 17 |
0.0453 |
1.15062 |
5.064 |
16.60992 |
19 |
2.9 |
| 18 |
0.0403 |
1.02362 |
6.385 |
20.9428 |
16 |
2.3 |
| 19 |
0.0359 |
0.91186 |
8.051 |
26.40728 |
14 |
1.8 |
| 20 |
0.032 |
0.8128 |
10.15 |
33.292 |
11 |
1.5 |
| 21 |
0.0285 |
0.7239 |
12.8 |
41.984 |
9 |
1.2 |
| 22 |
0.0254 |
0.64516 |
16.14 |
52.9392 |
7 |
0.92 |
| 23 |
0.0226 |
0.57404 |
20.36 |
66.7808 |
4.7 |
0.729 |
| 24 |
0.0201 |
0.51054 |
25.67 |
84.1976 |
3.5 |
0.577 |
| 25 |
0.0179 |
0.45466 |
32.37 |
106.1736 |
2.7 |
0.457 |
| 26 |
0.0159 |
0.40386 |
40.81 |
133.8568 |
2.2 |
0.361 |
| 27 |
0.0142 |
0.36068 |
51.47 |
168.8216 |
1.7 |
0.288 |
| 28 |
0.0126 |
0.32004 |
64.9 |
212.872 |
1.4 |
0.226 |
| 29 |
0.0113 |
0.28702 |
81.83 |
268.4024 |
1.2 |
0.182 |
| 30 |
0.01 |
0.254 |
103.2 |
338.496 |
0.86 |
0.142 |
| 31 |
0.0089 |
0.22606 |
130.1 |
426.728 |
0.7 |
0.113 |
| 32 |
0.008 |
0.2032 |
164.1 |
538.248 |
0.53 |
0.091 |
| Metric 2.0 |
0.00787 |
0.200 |
169.39 |
555.61 |
0.51 |
0.088 |
| 33 |
0.0071 |
0.18034 |
206.9 |
678.632 |
0.43 |
0.072 |
| Metric 1.8 |
0.00709 |
0.180 |
207.5 |
680.55 |
0.43 |
0.072 |
| 34 |
0.0063 |
0.16002 |
260.9 |
855.752 |
0.33 |
0.056 |
| Metric 1.6 |
0.0063 |
0.16002 |
260.9 |
855.752 |
0.33 |
0.056 |
| 35 |
0.0056 |
0.14224 |
329 |
1079.12 |
0.27 |
0.044 |
| Metric 1.4 |
.00551 |
.140 |
339 |
1114 |
0.26 |
0.043 |
| 36 |
0.005 |
0.127 |
414.8 |
1360 |
0.21 |
0.035 |
| Metric 1.25 |
.00492 |
0.125 |
428.2 |
1404 |
0.20 |
0.034 |
| 37 |
0.0045 |
0.1143 |
523.1 |
1715 |
0.17 |
0.0289 |
| Metric 1.12 |
.00441 |
0.112 |
533.8 |
1750 |
0.163 |
0.0277 |
| 38 |
0.004 |
0.1016 |
659.6 |
2163 |
0.13 |
0.0228 |
| Metric 1 |
.00394 |
0.1000 |
670.2 |
2198 |
0.126 |
0.0225 |
| 39 |
0.0035 |
0.0889 |
831.8 |
2728 |
0.11 |
0.0175 |
| 40 |
0.0031 |
0.07874 |
1049 |
3440 |
0.09 |
0.0137 |
| |
|
|
|
|
|
|
|
|
|
Voltage Drop Calculator
by electrician.com
The following calculator calculates the voltage drop, and voltage at the end of the wire for American Wire Gauge from 4/0 AWG to 30 AWG, aluminum or copper wire.
|
|
