Wiring - Determining Wire Size and Voltage Drop for Amps - 480/277 VAC
480 VAC WIRE SIZE |
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240 VAC PER LEG USING COPPER WIRE AND A 2% VOLTAGE DROP |
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AMPS | VA | #16 | #14 | #12 | #10 | #8 | #6 | #4 | #2 | 1/0 | 2/0 | 3/0 | 4/0 |
1 | 120 | 563 | 897 | 1425 | 2269 | 3600 | 5738 | 9098 | 14487 | 23127 | 29018 | 36655 | 46255 |
2 | 240 | 281 | 448 | 712 | 1135 | 1800 | 2869 | 4549 | 7244 | 11564 | 14509 | 18327 | 23127 |
3 | 360 | 188 | 299 | 475 | 756 | 1200 | 1913 | 3033 | 4829 | 7709 | 9673 | 12218 | 15418 |
4 | 480 | 141 | 224 | 356 | 567 | 900 | 1435 | 2275 | 3622 | 5782 | 7255 | 9164 | 11564 |
5 | 600 | 113 | 179 | 285 | 454 | 720 | 1148 | 1820 | 2897 | 4625 | 5804 | 7331 | 9251 |
10 | 1200 | 56 | 90 | 142 | 227 | 360 | 574 | 910 | 1449 | 2313 | 2902 | 3665 | 4625 |
15 | 1800 | 60 | 95 | 151 | 240 | 383 | 607 | 966 | 1542 | 1935 | 2444 | 3084 | |
20 | 2400 | 71 | 113 | 180 | 287 | 455 | 724 | 1156 | 1451 | 1833 | 2313 | ||
25 | 3000 | 91 | 144 | 230 | 364 | 579 | 925 | 1161 | 1466 | 1850 | |||
30 | 3600 | 76 | 120 | 191 | 303 | 483 | 771 | 967 | 1222 | 1542 | |||
35 | 4200 | 103 | 164 | 260 | 414 | 661 | 829 | 1047 | 1322 | ||||
40 | 4800 | 90 | 143 | 227 | 362 | 578 | 725 | 916 | 1156 | ||||
50 | 6000 | 115 | 182 | 290 | 463 | 580 | 733 | 925 | |||||
60 | 7200 | 152 | 241 | 385 | 484 | 611 | 771 | ||||||
70 | 8400 | 130 | 207 | 330 | 415 | 524 | 661 | ||||||
80 | 9600 | 181 | 289 | 363 | 458 | 578 | |||||||
90 | 10800 | 257 | 322 | 407 | 514 | ||||||||
100 | 12000 | 231 | 290 | 367 | 463 | ||||||||
125 | 15000 | 185 | 232 | 293 | 370 | ||||||||
150 | 18000 | 193 | 244 | 308 | |||||||||
175 | 21000 | 166 | 209 | 264 | |||||||||
200 | 24000 | 183 | 231 |
On the left column find the amps that your circuit must supply. Then follow that row to the right until you find the distance of your circuit from the supply to the equipment you are feeding. Don't forget to take into account going up and down walls and around any other obstacles. Then follow it up to find your minimum wire size.
This chart is only intended to be an educational guide. Consult the National Electric Code and other local ordinances.