Maximum Run Length Table
Copper and aluminum • Maximum one-way length in feet • 3% and 5% voltage drop
TL;DR
Choose copper or aluminum, then find your supply voltage, voltage-drop target, wire size and current. Each eligible cell gives the maximum one-way length in feet for a resistance-only conductor pair; a dash means the current exceeds the site ampacity limit or the conductor has no supported ampacity data. Check installation conditions and equipment voltage requirements before using the length.
How to use the tables
- Choose the conductor material, supply voltage and system, then the 3% or 5% drop table.
- Find your wire size row and load-current column. Read the one-way length; do not double the route length.
- Keep the installed route within that length, then check ampacity adjustments, terminations and the equipment’s minimum voltage. For other currents or voltages, use the maximum circuit length calculator.
Copper maximum run lengths
All lengths are one way, in ft. Values are rounded down to whole feet; less than 1 ft displays <1 and greater than 5000 ft displays >5000. A dash (—) means the current exceeds the site ampacity limit or no supported ampacity data exists, including 14 AWG aluminum. R is resistance in Ω/kft at the site’s 75°C reference; the row also shows the site ampacity limit.
Copper: 120V single-phase
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 38 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 60 | 45 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 96 | 72 | 48 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 154 | 115 | 77 | 57 | 46 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 244 | 183 | 122 | 91 | 73 | 61 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 389 | 292 | 194 | 146 | 116 | 97 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 489 | 367 | 244 | 183 | 146 | 122 | 73 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 618 | 463 | 309 | 231 | 185 | 154 | 92 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 779 | 584 | 389 | 292 | 233 | 194 | 116 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 983 | 737 | 491 | 368 | 295 | 245 | 147 | 98 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 1240 | 930 | 620 | 465 | 372 | 310 | 186 | 124 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 1566 | 1174 | 783 | 587 | 469 | 391 | 234 | 156 | 117 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 1973 | 1480 | 986 | 740 | 592 | 493 | 296 | 197 | 148 |
| 250 kcmil0.0515 Ω/kft · 255 A | 2330 | 1747 | 1165 | 873 | 699 | 582 | 349 | 233 | 174 |
| 300 kcmil0.0429 Ω/kft · 285 A | 2797 | 2097 | 1398 | 1048 | 839 | 699 | 419 | 279 | 209 |
| 350 kcmil0.0367 Ω/kft · 310 A | 3269 | 2452 | 1634 | 1226 | 980 | 817 | 490 | 326 | 245 |
| 400 kcmil0.0321 Ω/kft · 335 A | 3738 | 2803 | 1869 | 1401 | 1121 | 934 | 560 | 373 | 280 |
| 500 kcmil0.0258 Ω/kft · 380 A | 4651 | 3488 | 2325 | 1744 | 1395 | 1162 | 697 | 465 | 348 |
| 600 kcmil0.0214 Ω/kft · 420 A | >5000 | 4205 | 2803 | 2102 | 1682 | 1401 | 841 | 560 | 420 |
| 750 kcmil0.0171 Ω/kft · 475 A | >5000 | >5000 | 3508 | 2631 | 2105 | 1754 | 1052 | 701 | 526 |
| 1000 kcmil0.0129 Ω/kft · 545 A | >5000 | >5000 | 4651 | 3488 | 2790 | 2325 | 1395 | 930 | 697 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 63 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 101 | 75 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 161 | 120 | 80 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 257 | 192 | 128 | 96 | 77 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 407 | 305 | 203 | 152 | 122 | 101 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 649 | 487 | 324 | 243 | 194 | 162 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 816 | 612 | 408 | 306 | 244 | 204 | 122 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 1030 | 773 | 515 | 386 | 309 | 257 | 154 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 1298 | 974 | 649 | 487 | 389 | 324 | 194 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 1639 | 1229 | 819 | 614 | 491 | 409 | 245 | 163 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 2068 | 1551 | 1034 | 775 | 620 | 517 | 310 | 206 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 2610 | 1958 | 1305 | 979 | 783 | 652 | 391 | 261 | 195 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 3289 | 2467 | 1644 | 1233 | 986 | 822 | 493 | 328 | 246 |
| 250 kcmil0.0515 Ω/kft · 255 A | 3883 | 2912 | 1941 | 1456 | 1165 | 970 | 582 | 388 | 291 |
| 300 kcmil0.0429 Ω/kft · 285 A | 4662 | 3496 | 2331 | 1748 | 1398 | 1165 | 699 | 466 | 349 |
| 350 kcmil0.0367 Ω/kft · 310 A | >5000 | 4087 | 2724 | 2043 | 1634 | 1362 | 817 | 544 | 408 |
| 400 kcmil0.0321 Ω/kft · 335 A | >5000 | 4672 | 3115 | 2336 | 1869 | 1557 | 934 | 623 | 467 |
| 500 kcmil0.0258 Ω/kft · 380 A | >5000 | >5000 | 3875 | 2906 | 2325 | 1937 | 1162 | 775 | 581 |
| 600 kcmil0.0214 Ω/kft · 420 A | >5000 | >5000 | 4672 | 3504 | 2803 | 2336 | 1401 | 934 | 700 |
| 750 kcmil0.0171 Ω/kft · 475 A | >5000 | >5000 | >5000 | 4385 | 3508 | 2923 | 1754 | 1169 | 877 |
| 1000 kcmil0.0129 Ω/kft · 545 A | >5000 | >5000 | >5000 | >5000 | 4651 | 3875 | 2325 | 1550 | 1162 |
Copper: 240V single-phase
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 76 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 121 | 90 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 193 | 145 | 96 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 308 | 231 | 154 | 115 | 92 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 488 | 366 | 244 | 183 | 146 | 122 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 779 | 584 | 389 | 292 | 233 | 194 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 979 | 734 | 489 | 367 | 293 | 244 | 146 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 1237 | 927 | 618 | 463 | 371 | 309 | 185 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 1558 | 1168 | 779 | 584 | 467 | 389 | 233 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 1967 | 1475 | 983 | 737 | 590 | 491 | 295 | 196 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 2481 | 1861 | 1240 | 930 | 744 | 620 | 372 | 248 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 3133 | 2349 | 1566 | 1174 | 939 | 783 | 469 | 313 | 234 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 3947 | 2960 | 1973 | 1480 | 1184 | 986 | 592 | 394 | 296 |
| 250 kcmil0.0515 Ω/kft · 255 A | 4660 | 3495 | 2330 | 1747 | 1398 | 1165 | 699 | 466 | 349 |
| 300 kcmil0.0429 Ω/kft · 285 A | >5000 | 4195 | 2797 | 2097 | 1678 | 1398 | 839 | 559 | 419 |
| 350 kcmil0.0367 Ω/kft · 310 A | >5000 | 4904 | 3269 | 2452 | 1961 | 1634 | 980 | 653 | 490 |
| 400 kcmil0.0321 Ω/kft · 335 A | >5000 | >5000 | 3738 | 2803 | 2242 | 1869 | 1121 | 747 | 560 |
| 500 kcmil0.0258 Ω/kft · 380 A | >5000 | >5000 | 4651 | 3488 | 2790 | 2325 | 1395 | 930 | 697 |
| 600 kcmil0.0214 Ω/kft · 420 A | >5000 | >5000 | >5000 | 4205 | 3364 | 2803 | 1682 | 1121 | 841 |
| 750 kcmil0.0171 Ω/kft · 475 A | >5000 | >5000 | >5000 | >5000 | 4210 | 3508 | 2105 | 1403 | 1052 |
| 1000 kcmil0.0129 Ω/kft · 545 A | >5000 | >5000 | >5000 | >5000 | >5000 | 4651 | 2790 | 1860 | 1395 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 127 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 202 | 151 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 322 | 241 | 161 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 514 | 385 | 257 | 192 | 154 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 814 | 610 | 407 | 305 | 244 | 203 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 1298 | 974 | 649 | 487 | 389 | 324 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 1632 | 1224 | 816 | 612 | 489 | 408 | 244 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 2061 | 1546 | 1030 | 773 | 618 | 515 | 309 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 2597 | 1948 | 1298 | 974 | 779 | 649 | 389 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 3278 | 2459 | 1639 | 1229 | 983 | 819 | 491 | 327 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 4136 | 3102 | 2068 | 1551 | 1240 | 1034 | 620 | 413 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | >5000 | 3916 | 2610 | 1958 | 1566 | 1305 | 783 | 522 | 391 |
| 4/0 AWG0.0608 Ω/kft · 230 A | >5000 | 4934 | 3289 | 2467 | 1973 | 1644 | 986 | 657 | 493 |
| 250 kcmil0.0515 Ω/kft · 255 A | >5000 | >5000 | 3883 | 2912 | 2330 | 1941 | 1165 | 776 | 582 |
| 300 kcmil0.0429 Ω/kft · 285 A | >5000 | >5000 | 4662 | 3496 | 2797 | 2331 | 1398 | 932 | 699 |
| 350 kcmil0.0367 Ω/kft · 310 A | >5000 | >5000 | >5000 | 4087 | 3269 | 2724 | 1634 | 1089 | 817 |
| 400 kcmil0.0321 Ω/kft · 335 A | >5000 | >5000 | >5000 | 4672 | 3738 | 3115 | 1869 | 1246 | 934 |
| 500 kcmil0.0258 Ω/kft · 380 A | >5000 | >5000 | >5000 | >5000 | 4651 | 3875 | 2325 | 1550 | 1162 |
| 600 kcmil0.0214 Ω/kft · 420 A | >5000 | >5000 | >5000 | >5000 | >5000 | 4672 | 2803 | 1869 | 1401 |
| 750 kcmil0.0171 Ω/kft · 475 A | >5000 | >5000 | >5000 | >5000 | >5000 | >5000 | 3508 | 2339 | 1754 |
| 1000 kcmil0.0129 Ω/kft · 545 A | >5000 | >5000 | >5000 | >5000 | >5000 | >5000 | 4651 | 3100 | 2325 |
Copper: 12V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 3 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 6 | 4 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 9 | 7 | 4 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 15 | 11 | 7 | 5 | 4 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 24 | 18 | 12 | 9 | 7 | 6 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 38 | 29 | 19 | 14 | 11 | 9 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 48 | 36 | 24 | 18 | 14 | 12 | 7 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 61 | 46 | 30 | 23 | 18 | 15 | 9 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 77 | 58 | 38 | 29 | 23 | 19 | 11 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 98 | 73 | 49 | 36 | 29 | 24 | 14 | 9 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 124 | 93 | 62 | 46 | 37 | 31 | 18 | 12 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 156 | 117 | 78 | 58 | 46 | 39 | 23 | 15 | 11 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 197 | 148 | 98 | 74 | 59 | 49 | 29 | 19 | 14 |
| 250 kcmil0.0515 Ω/kft · 255 A | 233 | 174 | 116 | 87 | 69 | 58 | 34 | 23 | 17 |
| 300 kcmil0.0429 Ω/kft · 285 A | 279 | 209 | 139 | 104 | 83 | 69 | 41 | 27 | 20 |
| 350 kcmil0.0367 Ω/kft · 310 A | 326 | 245 | 163 | 122 | 98 | 81 | 49 | 32 | 24 |
| 400 kcmil0.0321 Ω/kft · 335 A | 373 | 280 | 186 | 140 | 112 | 93 | 56 | 37 | 28 |
| 500 kcmil0.0258 Ω/kft · 380 A | 465 | 348 | 232 | 174 | 139 | 116 | 69 | 46 | 34 |
| 600 kcmil0.0214 Ω/kft · 420 A | 560 | 420 | 280 | 210 | 168 | 140 | 84 | 56 | 42 |
| 750 kcmil0.0171 Ω/kft · 475 A | 701 | 526 | 350 | 263 | 210 | 175 | 105 | 70 | 52 |
| 1000 kcmil0.0129 Ω/kft · 545 A | 930 | 697 | 465 | 348 | 279 | 232 | 139 | 93 | 69 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 6 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 10 | 7 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 16 | 12 | 8 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 25 | 19 | 12 | 9 | 7 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 40 | 30 | 20 | 15 | 12 | 10 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 64 | 48 | 32 | 24 | 19 | 16 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 81 | 61 | 40 | 30 | 24 | 20 | 12 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 103 | 77 | 51 | 38 | 30 | 25 | 15 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 129 | 97 | 64 | 48 | 38 | 32 | 19 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 163 | 122 | 81 | 61 | 49 | 40 | 24 | 16 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 206 | 155 | 103 | 77 | 62 | 51 | 31 | 20 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 261 | 195 | 130 | 97 | 78 | 65 | 39 | 26 | 19 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 328 | 246 | 164 | 123 | 98 | 82 | 49 | 32 | 24 |
| 250 kcmil0.0515 Ω/kft · 255 A | 388 | 291 | 194 | 145 | 116 | 97 | 58 | 38 | 29 |
| 300 kcmil0.0429 Ω/kft · 285 A | 466 | 349 | 233 | 174 | 139 | 116 | 69 | 46 | 34 |
| 350 kcmil0.0367 Ω/kft · 310 A | 544 | 408 | 272 | 204 | 163 | 136 | 81 | 54 | 40 |
| 400 kcmil0.0321 Ω/kft · 335 A | 623 | 467 | 311 | 233 | 186 | 155 | 93 | 62 | 46 |
| 500 kcmil0.0258 Ω/kft · 380 A | 775 | 581 | 387 | 290 | 232 | 193 | 116 | 77 | 58 |
| 600 kcmil0.0214 Ω/kft · 420 A | 934 | 700 | 467 | 350 | 280 | 233 | 140 | 93 | 70 |
| 750 kcmil0.0171 Ω/kft · 475 A | 1169 | 877 | 584 | 438 | 350 | 292 | 175 | 116 | 87 |
| 1000 kcmil0.0129 Ω/kft · 545 A | 1550 | 1162 | 775 | 581 | 465 | 387 | 232 | 155 | 116 |
Copper: 24V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 7 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 12 | 9 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 19 | 14 | 9 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 30 | 23 | 15 | 11 | 9 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 48 | 36 | 24 | 18 | 14 | 12 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 77 | 58 | 38 | 29 | 23 | 19 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 97 | 73 | 48 | 36 | 29 | 24 | 14 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 123 | 92 | 61 | 46 | 37 | 30 | 18 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 155 | 116 | 77 | 58 | 46 | 38 | 23 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 196 | 147 | 98 | 73 | 59 | 49 | 29 | 19 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 248 | 186 | 124 | 93 | 74 | 62 | 37 | 24 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 313 | 234 | 156 | 117 | 93 | 78 | 46 | 31 | 23 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 394 | 296 | 197 | 148 | 118 | 98 | 59 | 39 | 29 |
| 250 kcmil0.0515 Ω/kft · 255 A | 466 | 349 | 233 | 174 | 139 | 116 | 69 | 46 | 34 |
| 300 kcmil0.0429 Ω/kft · 285 A | 559 | 419 | 279 | 209 | 167 | 139 | 83 | 55 | 41 |
| 350 kcmil0.0367 Ω/kft · 310 A | 653 | 490 | 326 | 245 | 196 | 163 | 98 | 65 | 49 |
| 400 kcmil0.0321 Ω/kft · 335 A | 747 | 560 | 373 | 280 | 224 | 186 | 112 | 74 | 56 |
| 500 kcmil0.0258 Ω/kft · 380 A | 930 | 697 | 465 | 348 | 279 | 232 | 139 | 93 | 69 |
| 600 kcmil0.0214 Ω/kft · 420 A | 1121 | 841 | 560 | 420 | 336 | 280 | 168 | 112 | 84 |
| 750 kcmil0.0171 Ω/kft · 475 A | 1403 | 1052 | 701 | 526 | 421 | 350 | 210 | 140 | 105 |
| 1000 kcmil0.0129 Ω/kft · 545 A | 1860 | 1395 | 930 | 697 | 558 | 465 | 279 | 186 | 139 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 12 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 20 | 15 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 32 | 24 | 16 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 51 | 38 | 25 | 19 | 15 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 81 | 61 | 40 | 30 | 24 | 20 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 129 | 97 | 64 | 48 | 38 | 32 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 163 | 122 | 81 | 61 | 48 | 40 | 24 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 206 | 154 | 103 | 77 | 61 | 51 | 30 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 259 | 194 | 129 | 97 | 77 | 64 | 38 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 327 | 245 | 163 | 122 | 98 | 81 | 49 | 32 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 413 | 310 | 206 | 155 | 124 | 103 | 62 | 41 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 522 | 391 | 261 | 195 | 156 | 130 | 78 | 52 | 39 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 657 | 493 | 328 | 246 | 197 | 164 | 98 | 65 | 49 |
| 250 kcmil0.0515 Ω/kft · 255 A | 776 | 582 | 388 | 291 | 233 | 194 | 116 | 77 | 58 |
| 300 kcmil0.0429 Ω/kft · 285 A | 932 | 699 | 466 | 349 | 279 | 233 | 139 | 93 | 69 |
| 350 kcmil0.0367 Ω/kft · 310 A | 1089 | 817 | 544 | 408 | 326 | 272 | 163 | 108 | 81 |
| 400 kcmil0.0321 Ω/kft · 335 A | 1246 | 934 | 623 | 467 | 373 | 311 | 186 | 124 | 93 |
| 500 kcmil0.0258 Ω/kft · 380 A | 1550 | 1162 | 775 | 581 | 465 | 387 | 232 | 155 | 116 |
| 600 kcmil0.0214 Ω/kft · 420 A | 1869 | 1401 | 934 | 700 | 560 | 467 | 280 | 186 | 140 |
| 750 kcmil0.0171 Ω/kft · 475 A | 2339 | 1754 | 1169 | 877 | 701 | 584 | 350 | 233 | 175 |
| 1000 kcmil0.0129 Ω/kft · 545 A | 3100 | 2325 | 1550 | 1162 | 930 | 775 | 465 | 310 | 232 |
Copper: 48V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 15 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 24 | 18 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 38 | 29 | 19 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 61 | 46 | 30 | 23 | 18 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 97 | 73 | 48 | 36 | 29 | 24 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 155 | 116 | 77 | 58 | 46 | 38 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 195 | 146 | 97 | 73 | 58 | 48 | 29 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 247 | 185 | 123 | 92 | 74 | 61 | 37 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 311 | 233 | 155 | 116 | 93 | 77 | 46 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 393 | 295 | 196 | 147 | 118 | 98 | 59 | 39 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 496 | 372 | 248 | 186 | 148 | 124 | 74 | 49 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 626 | 469 | 313 | 234 | 187 | 156 | 93 | 62 | 46 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 789 | 592 | 394 | 296 | 236 | 197 | 118 | 78 | 59 |
| 250 kcmil0.0515 Ω/kft · 255 A | 932 | 699 | 466 | 349 | 279 | 233 | 139 | 93 | 69 |
| 300 kcmil0.0429 Ω/kft · 285 A | 1118 | 839 | 559 | 419 | 335 | 279 | 167 | 111 | 83 |
| 350 kcmil0.0367 Ω/kft · 310 A | 1307 | 980 | 653 | 490 | 392 | 326 | 196 | 130 | 98 |
| 400 kcmil0.0321 Ω/kft · 335 A | 1495 | 1121 | 747 | 560 | 448 | 373 | 224 | 149 | 112 |
| 500 kcmil0.0258 Ω/kft · 380 A | 1860 | 1395 | 930 | 697 | 558 | 465 | 279 | 186 | 139 |
| 600 kcmil0.0214 Ω/kft · 420 A | 2242 | 1682 | 1121 | 841 | 672 | 560 | 336 | 224 | 168 |
| 750 kcmil0.0171 Ω/kft · 475 A | 2807 | 2105 | 1403 | 1052 | 842 | 701 | 421 | 280 | 210 |
| 1000 kcmil0.0129 Ω/kft · 545 A | 3720 | 2790 | 1860 | 1395 | 1116 | 930 | 558 | 372 | 279 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWG3.14 Ω/kft · 15 A | 25 | — | — | — | — | — | — | — | — |
| 12 AWG1.98 Ω/kft · 20 A | 40 | 30 | — | — | — | — | — | — | — |
| 10 AWG1.24 Ω/kft · 30 A | 64 | 48 | 32 | — | — | — | — | — | — |
| 8 AWG0.778 Ω/kft · 50 A | 102 | 77 | 51 | 38 | 30 | — | — | — | — |
| 6 AWG0.491 Ω/kft · 65 A | 162 | 122 | 81 | 61 | 48 | 40 | — | — | — |
| 4 AWG0.308 Ω/kft · 85 A | 259 | 194 | 129 | 97 | 77 | 64 | — | — | — |
| 3 AWG0.245 Ω/kft · 100 A | 326 | 244 | 163 | 122 | 97 | 81 | 48 | — | — |
| 2 AWG0.194 Ω/kft · 115 A | 412 | 309 | 206 | 154 | 123 | 103 | 61 | — | — |
| 1 AWG0.154 Ω/kft · 130 A | 519 | 389 | 259 | 194 | 155 | 129 | 77 | — | — |
| 1/0 AWG0.122 Ω/kft · 150 A | 655 | 491 | 327 | 245 | 196 | 163 | 98 | 65 | — |
| 2/0 AWG0.0967 Ω/kft · 175 A | 827 | 620 | 413 | 310 | 248 | 206 | 124 | 82 | — |
| 3/0 AWG0.0766 Ω/kft · 200 A | 1044 | 783 | 522 | 391 | 313 | 261 | 156 | 104 | 78 |
| 4/0 AWG0.0608 Ω/kft · 230 A | 1315 | 986 | 657 | 493 | 394 | 328 | 197 | 131 | 98 |
| 250 kcmil0.0515 Ω/kft · 255 A | 1553 | 1165 | 776 | 582 | 466 | 388 | 233 | 155 | 116 |
| 300 kcmil0.0429 Ω/kft · 285 A | 1864 | 1398 | 932 | 699 | 559 | 466 | 279 | 186 | 139 |
| 350 kcmil0.0367 Ω/kft · 310 A | 2179 | 1634 | 1089 | 817 | 653 | 544 | 326 | 217 | 163 |
| 400 kcmil0.0321 Ω/kft · 335 A | 2492 | 1869 | 1246 | 934 | 747 | 623 | 373 | 249 | 186 |
| 500 kcmil0.0258 Ω/kft · 380 A | 3100 | 2325 | 1550 | 1162 | 930 | 775 | 465 | 310 | 232 |
| 600 kcmil0.0214 Ω/kft · 420 A | 3738 | 2803 | 1869 | 1401 | 1121 | 934 | 560 | 373 | 280 |
| 750 kcmil0.0171 Ω/kft · 475 A | 4678 | 3508 | 2339 | 1754 | 1403 | 1169 | 701 | 467 | 350 |
| 1000 kcmil0.0129 Ω/kft · 545 A | >5000 | 4651 | 3100 | 2325 | 1860 | 1550 | 930 | 620 | 465 |
Aluminum maximum run lengths
All lengths are one way, in ft. Values are rounded down to whole feet; less than 1 ft displays <1 and greater than 5000 ft displays >5000. A dash (—) means the current exceeds the site ampacity limit or no supported ampacity data exists, including 14 AWG aluminum. R is resistance in Ω/kft at the site’s 75°C reference; the row also shows the site ampacity limit.
Aluminum: 120V single-phase
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 36 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 58 | 44 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 93 | 70 | 46 | 35 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 148 | 111 | 74 | 55 | 44 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 236 | 177 | 118 | 88 | 70 | 59 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 297 | 223 | 148 | 111 | 89 | 74 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 376 | 282 | 188 | 141 | 112 | 94 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 474 | 355 | 237 | 177 | 142 | 118 | 71 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 597 | 447 | 298 | 223 | 179 | 149 | 89 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 754 | 566 | 377 | 283 | 226 | 188 | 113 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 952 | 714 | 476 | 357 | 285 | 238 | 142 | 95 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 1200 | 900 | 600 | 450 | 360 | 300 | 180 | 120 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 1416 | 1062 | 708 | 531 | 425 | 354 | 212 | 141 | 106 |
| 300 kcmil0.0707 Ω/kft · 230 A | 1697 | 1272 | 848 | 636 | 509 | 424 | 254 | 169 | 127 |
| 350 kcmil0.0605 Ω/kft · 250 A | 1983 | 1487 | 991 | 743 | 595 | 495 | 297 | 198 | 148 |
| 400 kcmil0.0529 Ω/kft · 270 A | 2268 | 1701 | 1134 | 850 | 680 | 567 | 340 | 226 | 170 |
| 500 kcmil0.0424 Ω/kft · 310 A | 2830 | 2122 | 1415 | 1061 | 849 | 707 | 424 | 283 | 212 |
| 600 kcmil0.0353 Ω/kft · 340 A | 3399 | 2549 | 1699 | 1274 | 1019 | 849 | 509 | 339 | 254 |
| 750 kcmil0.0282 Ω/kft · 385 A | 4255 | 3191 | 2127 | 1595 | 1276 | 1063 | 638 | 425 | 319 |
| 1000 kcmil0.0212 Ω/kft · 445 A | >5000 | 4245 | 2830 | 2122 | 1698 | 1415 | 849 | 566 | 424 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 61 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 98 | 73 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 156 | 117 | 78 | 58 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 247 | 185 | 123 | 92 | 74 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 393 | 295 | 196 | 147 | 118 | 98 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 496 | 372 | 248 | 186 | 148 | 124 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 626 | 470 | 313 | 235 | 188 | 156 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 790 | 592 | 395 | 296 | 237 | 197 | 118 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 995 | 746 | 497 | 373 | 298 | 248 | 149 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 1257 | 943 | 628 | 471 | 377 | 314 | 188 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 1587 | 1190 | 793 | 595 | 476 | 396 | 238 | 158 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 2000 | 1500 | 1000 | 750 | 600 | 500 | 300 | 200 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 2361 | 1770 | 1180 | 885 | 708 | 590 | 354 | 236 | 177 |
| 300 kcmil0.0707 Ω/kft · 230 A | 2828 | 2121 | 1414 | 1060 | 848 | 707 | 424 | 282 | 212 |
| 350 kcmil0.0605 Ω/kft · 250 A | 3305 | 2479 | 1652 | 1239 | 991 | 826 | 495 | 330 | 247 |
| 400 kcmil0.0529 Ω/kft · 270 A | 3780 | 2835 | 1890 | 1417 | 1134 | 945 | 567 | 378 | 283 |
| 500 kcmil0.0424 Ω/kft · 310 A | 4716 | 3537 | 2358 | 1768 | 1415 | 1179 | 707 | 471 | 353 |
| 600 kcmil0.0353 Ω/kft · 340 A | >5000 | 4249 | 2832 | 2124 | 1699 | 1416 | 849 | 566 | 424 |
| 750 kcmil0.0282 Ω/kft · 385 A | >5000 | >5000 | 3546 | 2659 | 2127 | 1773 | 1063 | 709 | 531 |
| 1000 kcmil0.0212 Ω/kft · 445 A | >5000 | >5000 | 4716 | 3537 | 2830 | 2358 | 1415 | 943 | 707 |
Aluminum: 240V single-phase
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 73 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 117 | 88 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 187 | 140 | 93 | 70 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 297 | 222 | 148 | 111 | 89 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 472 | 354 | 236 | 177 | 141 | 118 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 595 | 446 | 297 | 223 | 178 | 148 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 752 | 564 | 376 | 282 | 225 | 188 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 948 | 711 | 474 | 355 | 284 | 237 | 142 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 1194 | 895 | 597 | 447 | 358 | 298 | 179 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 1509 | 1132 | 754 | 566 | 452 | 377 | 226 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 1904 | 1428 | 952 | 714 | 571 | 476 | 285 | 190 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 2400 | 1800 | 1200 | 900 | 720 | 600 | 360 | 240 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 2833 | 2125 | 1416 | 1062 | 850 | 708 | 425 | 283 | 212 |
| 300 kcmil0.0707 Ω/kft · 230 A | 3394 | 2545 | 1697 | 1272 | 1018 | 848 | 509 | 339 | 254 |
| 350 kcmil0.0605 Ω/kft · 250 A | 3966 | 2975 | 1983 | 1487 | 1190 | 991 | 595 | 396 | 297 |
| 400 kcmil0.0529 Ω/kft · 270 A | 4536 | 3402 | 2268 | 1701 | 1361 | 1134 | 680 | 453 | 340 |
| 500 kcmil0.0424 Ω/kft · 310 A | >5000 | 4245 | 2830 | 2122 | 1698 | 1415 | 849 | 566 | 424 |
| 600 kcmil0.0353 Ω/kft · 340 A | >5000 | >5000 | 3399 | 2549 | 2039 | 1699 | 1019 | 679 | 509 |
| 750 kcmil0.0282 Ω/kft · 385 A | >5000 | >5000 | 4255 | 3191 | 2553 | 2127 | 1276 | 851 | 638 |
| 1000 kcmil0.0212 Ω/kft · 445 A | >5000 | >5000 | >5000 | 4245 | 3396 | 2830 | 1698 | 1132 | 849 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 123 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 196 | 147 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 312 | 234 | 156 | 117 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 495 | 371 | 247 | 185 | 148 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 787 | 590 | 393 | 295 | 236 | 196 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 992 | 744 | 496 | 372 | 297 | 248 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 1253 | 940 | 626 | 470 | 376 | 313 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 1581 | 1185 | 790 | 592 | 474 | 395 | 237 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 1990 | 1492 | 995 | 746 | 597 | 497 | 298 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 2515 | 1886 | 1257 | 943 | 754 | 628 | 377 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 3174 | 2380 | 1587 | 1190 | 952 | 793 | 476 | 317 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 4000 | 3000 | 2000 | 1500 | 1200 | 1000 | 600 | 400 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 4722 | 3541 | 2361 | 1770 | 1416 | 1180 | 708 | 472 | 354 |
| 300 kcmil0.0707 Ω/kft · 230 A | >5000 | 4243 | 2828 | 2121 | 1697 | 1414 | 848 | 565 | 424 |
| 350 kcmil0.0605 Ω/kft · 250 A | >5000 | 4958 | 3305 | 2479 | 1983 | 1652 | 991 | 661 | 495 |
| 400 kcmil0.0529 Ω/kft · 270 A | >5000 | >5000 | 3780 | 2835 | 2268 | 1890 | 1134 | 756 | 567 |
| 500 kcmil0.0424 Ω/kft · 310 A | >5000 | >5000 | 4716 | 3537 | 2830 | 2358 | 1415 | 943 | 707 |
| 600 kcmil0.0353 Ω/kft · 340 A | >5000 | >5000 | >5000 | 4249 | 3399 | 2832 | 1699 | 1133 | 849 |
| 750 kcmil0.0282 Ω/kft · 385 A | >5000 | >5000 | >5000 | >5000 | 4255 | 3546 | 2127 | 1418 | 1063 |
| 1000 kcmil0.0212 Ω/kft · 445 A | >5000 | >5000 | >5000 | >5000 | >5000 | 4716 | 2830 | 1886 | 1415 |
Aluminum: 12V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 3 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 5 | 4 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 9 | 7 | 4 | 3 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 14 | 11 | 7 | 5 | 4 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 23 | 17 | 11 | 8 | 7 | 5 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 29 | 22 | 14 | 11 | 8 | 7 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 37 | 28 | 18 | 14 | 11 | 9 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 47 | 35 | 23 | 17 | 14 | 11 | 7 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 59 | 44 | 29 | 22 | 17 | 14 | 8 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 75 | 56 | 37 | 28 | 22 | 18 | 11 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 95 | 71 | 47 | 35 | 28 | 23 | 14 | 9 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 120 | 90 | 60 | 45 | 36 | 30 | 18 | 12 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 141 | 106 | 70 | 53 | 42 | 35 | 21 | 14 | 10 |
| 300 kcmil0.0707 Ω/kft · 230 A | 169 | 127 | 84 | 63 | 50 | 42 | 25 | 16 | 12 |
| 350 kcmil0.0605 Ω/kft · 250 A | 198 | 148 | 99 | 74 | 59 | 49 | 29 | 19 | 14 |
| 400 kcmil0.0529 Ω/kft · 270 A | 226 | 170 | 113 | 85 | 68 | 56 | 34 | 22 | 17 |
| 500 kcmil0.0424 Ω/kft · 310 A | 283 | 212 | 141 | 106 | 84 | 70 | 42 | 28 | 21 |
| 600 kcmil0.0353 Ω/kft · 340 A | 339 | 254 | 169 | 127 | 101 | 84 | 50 | 33 | 25 |
| 750 kcmil0.0282 Ω/kft · 385 A | 425 | 319 | 212 | 159 | 127 | 106 | 63 | 42 | 31 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 566 | 424 | 283 | 212 | 169 | 141 | 84 | 56 | 42 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 6 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 9 | 7 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 15 | 11 | 7 | 5 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 24 | 18 | 12 | 9 | 7 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 39 | 29 | 19 | 14 | 11 | 9 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 49 | 37 | 24 | 18 | 14 | 12 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 62 | 47 | 31 | 23 | 18 | 15 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 79 | 59 | 39 | 29 | 23 | 19 | 11 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 99 | 74 | 49 | 37 | 29 | 24 | 14 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 125 | 94 | 62 | 47 | 37 | 31 | 18 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 158 | 119 | 79 | 59 | 47 | 39 | 23 | 15 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 200 | 150 | 100 | 75 | 60 | 50 | 30 | 20 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 236 | 177 | 118 | 88 | 70 | 59 | 35 | 23 | 17 |
| 300 kcmil0.0707 Ω/kft · 230 A | 282 | 212 | 141 | 106 | 84 | 70 | 42 | 28 | 21 |
| 350 kcmil0.0605 Ω/kft · 250 A | 330 | 247 | 165 | 123 | 99 | 82 | 49 | 33 | 24 |
| 400 kcmil0.0529 Ω/kft · 270 A | 378 | 283 | 189 | 141 | 113 | 94 | 56 | 37 | 28 |
| 500 kcmil0.0424 Ω/kft · 310 A | 471 | 353 | 235 | 176 | 141 | 117 | 70 | 47 | 35 |
| 600 kcmil0.0353 Ω/kft · 340 A | 566 | 424 | 283 | 212 | 169 | 141 | 84 | 56 | 42 |
| 750 kcmil0.0282 Ω/kft · 385 A | 709 | 531 | 354 | 265 | 212 | 177 | 106 | 70 | 53 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 943 | 707 | 471 | 353 | 283 | 235 | 141 | 94 | 70 |
Aluminum: 24V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 7 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 11 | 8 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 18 | 14 | 9 | 7 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 29 | 22 | 14 | 11 | 8 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 47 | 35 | 23 | 17 | 14 | 11 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 59 | 44 | 29 | 22 | 17 | 14 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 75 | 56 | 37 | 28 | 22 | 18 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 94 | 71 | 47 | 35 | 28 | 23 | 14 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 119 | 89 | 59 | 44 | 35 | 29 | 17 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 150 | 113 | 75 | 56 | 45 | 37 | 22 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 190 | 142 | 95 | 71 | 57 | 47 | 28 | 19 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 240 | 180 | 120 | 90 | 72 | 60 | 36 | 24 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 283 | 212 | 141 | 106 | 85 | 70 | 42 | 28 | 21 |
| 300 kcmil0.0707 Ω/kft · 230 A | 339 | 254 | 169 | 127 | 101 | 84 | 50 | 33 | 25 |
| 350 kcmil0.0605 Ω/kft · 250 A | 396 | 297 | 198 | 148 | 119 | 99 | 59 | 39 | 29 |
| 400 kcmil0.0529 Ω/kft · 270 A | 453 | 340 | 226 | 170 | 136 | 113 | 68 | 45 | 34 |
| 500 kcmil0.0424 Ω/kft · 310 A | 566 | 424 | 283 | 212 | 169 | 141 | 84 | 56 | 42 |
| 600 kcmil0.0353 Ω/kft · 340 A | 679 | 509 | 339 | 254 | 203 | 169 | 101 | 67 | 50 |
| 750 kcmil0.0282 Ω/kft · 385 A | 851 | 638 | 425 | 319 | 255 | 212 | 127 | 85 | 63 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 1132 | 849 | 566 | 424 | 339 | 283 | 169 | 113 | 84 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 12 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 19 | 14 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 31 | 23 | 15 | 11 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 49 | 37 | 24 | 18 | 14 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 78 | 59 | 39 | 29 | 23 | 19 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 99 | 74 | 49 | 37 | 29 | 24 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 125 | 94 | 62 | 47 | 37 | 31 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 158 | 118 | 79 | 59 | 47 | 39 | 23 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 199 | 149 | 99 | 74 | 59 | 49 | 29 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 251 | 188 | 125 | 94 | 75 | 62 | 37 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 317 | 238 | 158 | 119 | 95 | 79 | 47 | 31 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 400 | 300 | 200 | 150 | 120 | 100 | 60 | 40 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 472 | 354 | 236 | 177 | 141 | 118 | 70 | 47 | 35 |
| 300 kcmil0.0707 Ω/kft · 230 A | 565 | 424 | 282 | 212 | 169 | 141 | 84 | 56 | 42 |
| 350 kcmil0.0605 Ω/kft · 250 A | 661 | 495 | 330 | 247 | 198 | 165 | 99 | 66 | 49 |
| 400 kcmil0.0529 Ω/kft · 270 A | 756 | 567 | 378 | 283 | 226 | 189 | 113 | 75 | 56 |
| 500 kcmil0.0424 Ω/kft · 310 A | 943 | 707 | 471 | 353 | 283 | 235 | 141 | 94 | 70 |
| 600 kcmil0.0353 Ω/kft · 340 A | 1133 | 849 | 566 | 424 | 339 | 283 | 169 | 113 | 84 |
| 750 kcmil0.0282 Ω/kft · 385 A | 1418 | 1063 | 709 | 531 | 425 | 354 | 212 | 141 | 106 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 1886 | 1415 | 943 | 707 | 566 | 471 | 283 | 188 | 141 |
Aluminum: 48V DC
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 14 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 23 | 17 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 37 | 28 | 18 | 14 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 59 | 44 | 29 | 22 | 17 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 94 | 70 | 47 | 35 | 28 | 23 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 119 | 89 | 59 | 44 | 35 | 29 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 150 | 112 | 75 | 56 | 45 | 37 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 189 | 142 | 94 | 71 | 56 | 47 | 28 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 238 | 179 | 119 | 89 | 71 | 59 | 35 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 301 | 226 | 150 | 113 | 90 | 75 | 45 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 380 | 285 | 190 | 142 | 114 | 95 | 57 | 38 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 480 | 360 | 240 | 180 | 144 | 120 | 72 | 48 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 566 | 425 | 283 | 212 | 170 | 141 | 85 | 56 | 42 |
| 300 kcmil0.0707 Ω/kft · 230 A | 678 | 509 | 339 | 254 | 203 | 169 | 101 | 67 | 50 |
| 350 kcmil0.0605 Ω/kft · 250 A | 793 | 595 | 396 | 297 | 238 | 198 | 119 | 79 | 59 |
| 400 kcmil0.0529 Ω/kft · 270 A | 907 | 680 | 453 | 340 | 272 | 226 | 136 | 90 | 68 |
| 500 kcmil0.0424 Ω/kft · 310 A | 1132 | 849 | 566 | 424 | 339 | 283 | 169 | 113 | 84 |
| 600 kcmil0.0353 Ω/kft · 340 A | 1359 | 1019 | 679 | 509 | 407 | 339 | 203 | 135 | 101 |
| 750 kcmil0.0282 Ω/kft · 385 A | 1702 | 1276 | 851 | 638 | 510 | 425 | 255 | 170 | 127 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 2264 | 1698 | 1132 | 849 | 679 | 566 | 339 | 226 | 169 |
| Wire size · R · ampacity | 15 A | 20 A | 30 A | 40 A | 50 A | 60 A | 100 A | 150 A | 200 A |
|---|---|---|---|---|---|---|---|---|---|
| 14 AWGNo supported ampacity data | — | — | — | — | — | — | — | — | — |
| 12 AWG3.25 Ω/kft · 15 A | 24 | — | — | — | — | — | — | — | — |
| 10 AWG2.04 Ω/kft · 25 A | 39 | 29 | — | — | — | — | — | — | — |
| 8 AWG1.28 Ω/kft · 40 A | 62 | 46 | 31 | 23 | — | — | — | — | — |
| 6 AWG0.808 Ω/kft · 50 A | 99 | 74 | 49 | 37 | 29 | — | — | — | — |
| 4 AWG0.508 Ω/kft · 65 A | 157 | 118 | 78 | 59 | 47 | 39 | — | — | — |
| 3 AWG0.403 Ω/kft · 75 A | 198 | 148 | 99 | 74 | 59 | 49 | — | — | — |
| 2 AWG0.319 Ω/kft · 90 A | 250 | 188 | 125 | 94 | 75 | 62 | — | — | — |
| 1 AWG0.253 Ω/kft · 100 A | 316 | 237 | 158 | 118 | 94 | 79 | 47 | — | — |
| 1/0 AWG0.201 Ω/kft · 120 A | 398 | 298 | 199 | 149 | 119 | 99 | 59 | — | — |
| 2/0 AWG0.159 Ω/kft · 135 A | 503 | 377 | 251 | 188 | 150 | 125 | 75 | — | — |
| 3/0 AWG0.126 Ω/kft · 155 A | 634 | 476 | 317 | 238 | 190 | 158 | 95 | 63 | — |
| 4/0 AWG0.1 Ω/kft · 180 A | 800 | 600 | 400 | 300 | 240 | 200 | 120 | 80 | — |
| 250 kcmil0.0847 Ω/kft · 205 A | 944 | 708 | 472 | 354 | 283 | 236 | 141 | 94 | 70 |
| 300 kcmil0.0707 Ω/kft · 230 A | 1131 | 848 | 565 | 424 | 339 | 282 | 169 | 113 | 84 |
| 350 kcmil0.0605 Ω/kft · 250 A | 1322 | 991 | 661 | 495 | 396 | 330 | 198 | 132 | 99 |
| 400 kcmil0.0529 Ω/kft · 270 A | 1512 | 1134 | 756 | 567 | 453 | 378 | 226 | 151 | 113 |
| 500 kcmil0.0424 Ω/kft · 310 A | 1886 | 1415 | 943 | 707 | 566 | 471 | 283 | 188 | 141 |
| 600 kcmil0.0353 Ω/kft · 340 A | 2266 | 1699 | 1133 | 849 | 679 | 566 | 339 | 226 | 169 |
| 750 kcmil0.0282 Ω/kft · 385 A | 2836 | 2127 | 1418 | 1063 | 851 | 709 | 425 | 283 | 212 |
| 1000 kcmil0.0212 Ω/kft · 445 A | 3773 | 2830 | 1886 | 1415 | 1132 | 943 | 566 | 377 | 283 |
Formula and assumptions
Vd = 2 × I × L × R / 1000
Lmax = (p × V × 1000) / (2 × I × R)
V is supply voltage, I is current in amperes, L is one-way length in feet, R is conductor resistance in Ω/kft, and p is 0.03 or 0.05. The factor of two includes the outgoing and return conductors of one conductor pair. These tables cover single-phase and DC only, with one set of conductors and a lumped load at the end.
Resistance comes directly from the site’s existing 75°C conductor resistance data, referenced to NEC Chapter 9 Table 8. Ampacity uses the site’s 75°C Table 310.16 values with NEC 240.4(D) small-conductor limits. The row labels expose both inputs so every cell can be recalculated. NIST’s Copper Wire Tables provides background on copper resistance; it does not supply the aluminum dataset.
This is a resistance-only model: it ignores AC reactance, power factor, temperature corrections and any voltage-drop margin already used upstream. The 3% and 5% columns are separate planning targets, not additional allowances to add together. No installation derating, continuous-load allowance or terminal-rating adjustment is applied.
Large-conductor AC systems require a full AC calculation. Use the AC calculator for impedance and power factor, the wire size calculator to compare conductor choices, and the maximum circuit length calculator for custom inputs.
Download the data
CSV files contain the same eligible cells as the tables, with unrounded numeric lengths in feet, including values below 1 ft and above 5000 ft. Unsupported and over-ampacity combinations are omitted. To reproduce the displayed table, apply the rounding and display rules above. These are calculated reference values, not field measurements.
Frequently Asked Questions
How far can 12 AWG copper run at 20A and 120V with 3% voltage drop?
The table shows 45 ft one way. The calculation is (0.03 × 120 × 1000) / (2 × 20 × 1.98) = 45.4545… ft, rounded down. This is at the site’s 20A small-conductor limit.
What is the 24V DC limit for 10 AWG copper at 30A and 5% drop?
The table shows 16 ft one way: (0.05 × 24 × 1000) / (2 × 30 × 1.24) = 16.1290… ft, rounded down. The outgoing and return conductors are already included by the factor of two.
How far can 4 AWG aluminum run at 60A and 240V with 3% drop?
The table shows 118 ft one way: (0.03 × 240 × 1000) / (2 × 60 × 0.508) = 118.1102… ft, rounded down. The site ampacity limit is 65A; AC reactance and installation adjustments are not included.
Why are some cells blank, including every 14 AWG aluminum cell?
A dash (—) means the chosen current exceeds the site ampacity limit or the conductor has no supported ampacity data. For example, 12 AWG copper is limited to 20A here, so its 30A cell is a dash. The site has no supported 14 AWG aluminum ampacity; those cells are all dashes and are omitted from the CSV.
Sources and references
- NFPA 70 — National Electrical Code
Code reference for conductor properties (Chapter 9 Table 8), ampacity (Table 310.16), and small-conductor limits (240.4(D)); calculations use the site’s existing resistance and ampacity data.
- NIST / NBS Circular 31 — Copper Wire Tables
Background on copper resistance and temperature dependence. This historical copper reference is not the source for aluminum values or a claim of exact equivalence to every site resistance value.
Hommer Zhao
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