Voltage Drop Calculations
To Find Volts Lost:
- Multiply current (amperes) by the distance (feet in one conductor) by the figure in the table below for the type of system and wire used.
- Place a decimal in front of the last six figures.
- The result is the number of volts lost.
Note: For AC 3 Phase Current Voltage Drop obtained is phase-to-phase.
| Wire Size | Power Factor % | AC Single Phase | AC Three Phase | DC |
|---|---|---|---|---|
| 14 AWG |
100 90 80 70 60 |
5880 5360 4790 4230 3650 |
5090 4640 4150 3660 3160 |
5880 |
| 12 AWG |
100 90 80 70 60 |
3690 3380 3030 2680 2320 |
3190 2930 2620 2320 2010 |
3690 |
| 10 AWG |
100 90 80 70 60 |
2320 2150 1935 1718 1497 |
2010 1861 1675 1487 1296 |
2820 |
| 8 AWG |
100 90 80 70 60 |
1462 1373 1248 1117 981 |
1265 1189 1081 969 849 |
1462 |
| 6 AWG |
100 90 80 70 60 |
918 882 812 734 653 |
795 764 703 636 565 |
918 |
| 4 AWG |
100 90 80 70 60 |
578 571 533 489 440 |
501 494 462 423 381 |
578 |
| 2 AWG |
100 90 80 70 60 |
367 379 361 337 309 |
318 328 313 292 268 |
363 |
| 1 AWG | 100
90 80 70 60 |
291 311 299 284 264 |
252 269 259 246 229 |
288 |
| 1/0 AWG |
100 90 80 70 60 |
233 257 252 241 227 |
202 222 218 209 106 |
229 |
| 2/0 AWG |
100 90 80 70 60 |
187 213 212 206 193 |
162 184 183 178 169 |
181 |
| 3/0 AWG |
100 90 80 70 60 |
149 179 181 177 171 |
129 155 156 153 148 |
144 |
| 4/0 AWG |
100 90 80 70 60 |
121 152 156 155 151 |
104 131 135 134 131 |
114 |
| 250 kcmil |
100 90 80 70 60 |
102 136 143 143 141 |
89 117 123 124 122 |
97 |
| 300 kcmil |
100 90 80 70 60 |
86 121 128 131 130 |
75 104 111 113 113 |
81 |
| 350 kcmil |
100 90 80 70 60 |
74 109 118 122 122 |
64 95 102 105 106 |
69 |
| 400 kcmil |
100 90 80 70 60 |
66 101 111 115 116 |
57 88 96 99 101 |
60 |
| 500 kcmil |
100 90 80 70 60 |
54 89 99 105 108 |
47 78 86 91 93 |
48 |
| 600 kcmil | 100
90 80 70 60 |
47 83 93 99 103 |
41 72 81 86 89 |
40 |
| 750 kcmil |
100 90 80 70 60 |
39 75 86 93 97 |
34 65 75 81 84 |
32 |
| 1000 kcmil | 100
90 80 70 60 |
31 67 79 86 91 |
27 58 68 75 78 |
24 |
To learn more about voltage drop, read Voltage Drop: Picking the Right Cable for the Long Run.