Online Calculators and Tables to Help You Determine Proper Wire Size
The ampacity chart below shows the allowable ampacities of single-insulated electrical wire rated up to and including 2000 Volts in free air, based on Ambient Air Temperature of 40°C (104°F).
Wire Size Chart:
Allowable Ampacities of Conductors in Free Air
| SIZE | 150°C (302°F) |
200°C (392°F) |
250°C (482°F) |
150°C (482°F) |
|---|---|---|---|---|
| AWG or kcmil |
TINNED COPPER | TINNED COPPER NPC 2%-10% |
NPC 2%-10% | ALUMINUM |
| 14 | 46 | 54 | 59 | - |
| 12 | 60 | 68 | 78 | 47 |
| 10 | 80 | 90 | 107 | 63 |
| 8 | 106 | 124 | 142 | 83 |
| 6 | 155 | 165 | 205 | 112 |
| 4 | 190 | 220 | 278 | 148 |
| 3 | 214 | 252 | 327 | 170 |
| 2 | 255 | 293 | 381 | 198 |
| 1 | 293 | 344 | 440 | 228 |
| 1/0 | 339 | 399 | 532 | 263 |
| 2/0 | 390 | 467 | 591 | 305 |
| 3/0 | 451 | 546 | 708 | 351 |
| 4/0 | 529 | 629 | 830 | 411 |
Note: View additional wire size charts from the list below.
Maximum Allowable Ampacities for Conductors in Raceway, Cable or Earth (30°C)
Maximum Allowable Ampacities for Conductors in Free Air (30°C)
Maximum Allowable Ampacities for Conductors in Raceway, Cable, or Earth (40°C)
For ambient temperatures other than 40°C, Correction Factors must be taken into consideration.
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