Electrical References
Wire size is determined by amperage and distance. The chart below tells you the wire size you need for 480/277 VAC.
480 VAC Wire Size 277 VAC per leg using copper wire and a 2% voltage drop
277 VAC per leg using copper wire and a 2% voltage drop.
| AMPS | #14 | #12 | #10 | #8 | #6 | #4 | #2 | 1/0 | 2/0 | 3/0 | 4/0 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 60 ft | 95 ft | 151 ft | 240 ft | 383 ft | 607 ft | 966 ft | 1542 ft | 1935 ft | 2444 ft | 3084 ft |
| 20 |
|
71 ft | 113 ft | 180 ft | 287 ft | 455 ft | 724 ft | 1156 ft | 1451 ft | 1833 ft | 2313 ft |
| 25 |
|
|
91 ft | 144 ft | 230 ft | 364 ft | 579 ft | 925 ft | 1161 ft | 1466 ft | 1850 ft |
| 30 |
|
|
76 ft | 120 ft | 191 ft | 303 ft | 483 ft | 771 ft | 967 ft | 1222 ft | 1542 ft |
| 35 |
|
|
|
103 ft | 164 ft | 260 ft | 414 ft | 661 ft | 829 ft | 1047 ft | 1322 ft |
| 40 |
|
|
|
90 ft | 143 ft | 227 ft | 362 ft | 578 ft | 725 ft | 916 ft | 1156 ft |
| 50 |
|
|
|
|
115 ft | 182 ft | 290 ft | 463 ft | 580 ft | 733 ft | 925 ft |
| 60 |
|
|
|
|
|
152 ft | 241 ft | 385 ft | 484 ft | 611 ft | 771 ft |
| 70 |
|
|
|
|
|
130 ft | 207 ft | 330 ft | 415 ft | 524 ft | 661 ft |
| 80 |
|
|
|
|
|
|
181 ft | 289 ft | 363 ft | 458 ft | 578 ft |
| 90 |
|
|
|
|
|
|
|
257 ft | 322 ft | 407 ft | 514 ft |
| 100 |
|
|
|
|
|
|
|
231 ft | 290 ft | 367 ft | 463 ft |
| 125 |
|
|
|
|
|
|
|
185 ft | 232 ft | 293 ft | 370 ft |
| 150 |
|
|
|
|
|
|
|
|
193 ft | 244 ft | 308 ft |
| 175 |
|
|
|
|
|
|
|
|
166 ft | 209 ft | 264 ft |
| 200 |
|
|
|
|
|
|
|
|
|
183 ft | 231 ft |
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.