Wire Ampacity Chart
Complete ampacity calculations for all wire sizes per NEC 2023 Table 310.16. Each page shows the full derating sequence, not just the table value. Base ampacity temp correction bundling 110.14(C) termination limit.
Copper THHN
| Wire | 90°C | 75°C | 60°C | Usable |
|---|---|---|---|---|
| 14 AWG | 25A | 20A | 15A | 20A |
| 12 AWG | 30A | 25A | 20A | 25A |
| 10 AWG | 40A | 35A | 30A | 35A |
| 8 AWG | 55A | 50A | 40A | 50A |
| 6 AWG | 75A | 65A | 55A | 65A |
| 4 AWG | 95A | 85A | 70A | 85A |
| 3 AWG | 115A | 100A | 85A | 100A |
| 2 AWG | 130A | 115A | 95A | 115A |
| 1 AWG | 145A | 130A | 110A | 130A |
| 1/0 AWG | 170A | 150A | 125A | 150A |
| 2/0 AWG | 195A | 175A | 145A | 175A |
| 3/0 AWG | 225A | 200A | 165A | 200A |
| 4/0 AWG | 260A | 230A | 195A | 230A |
Aluminum THHN
| Wire | 90°C | 75°C | 60°C | Usable |
|---|---|---|---|---|
| 12 AWG | 25A | 20A | 15A | 20A |
| 10 AWG | 35A | 30A | 25A | 30A |
| 8 AWG | 45A | 40A | 35A | 40A |
| 6 AWG | 55A | 50A | 40A | 50A |
| 4 AWG | 75A | 65A | 55A | 65A |
| 3 AWG | 85A | 75A | 65A | 75A |
| 2 AWG | 100A | 90A | 75A | 90A |
| 1 AWG | 115A | 100A | 85A | 100A |
| 1/0 AWG | 135A | 120A | 100A | 120A |
| 2/0 AWG | 150A | 135A | 115A | 135A |
| 3/0 AWG | 175A | 155A | 130A | 155A |
| 4/0 AWG | 205A | 180A | 150A | 180A |
Copper XHHW-2
| Wire | 90°C | 75°C | Usable |
|---|---|---|---|
| 14 AWG | 25A | 20A | 20A |
| 12 AWG | 30A | 25A | 25A |
| 10 AWG | 40A | 35A | 35A |
| 8 AWG | 55A | 50A | 50A |
| 6 AWG | 75A | 65A | 65A |
| 4 AWG | 95A | 85A | 85A |
| 3 AWG | 115A | 100A | 100A |
| 2 AWG | 130A | 115A | 115A |
| 1 AWG | 145A | 130A | 130A |
| 1/0 AWG | 170A | 150A | 150A |
| 2/0 AWG | 195A | 175A | 175A |
| 3/0 AWG | 225A | 200A | 200A |
| 4/0 AWG | 260A | 230A | 230A |
Aluminum XHHW-2
| Wire | 90°C | 75°C | Usable |
|---|---|---|---|
| 12 AWG | 25A | 20A | 20A |
| 10 AWG | 35A | 30A | 30A |
| 8 AWG | 45A | 40A | 40A |
| 6 AWG | 55A | 50A | 50A |
| 4 AWG | 75A | 65A | 65A |
| 3 AWG | 85A | 75A | 75A |
| 2 AWG | 100A | 90A | 90A |
| 1 AWG | 115A | 100A | 100A |
| 1/0 AWG | 135A | 120A | 120A |
| 2/0 AWG | 150A | 135A | 135A |
| 3/0 AWG | 175A | 155A | 155A |
| 4/0 AWG | 205A | 180A | 180A |
Copper NM-B (Romex)
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Important: For reference only. Not a substitute for a licensed electrician. Electrical work can cause serious injury, death, fire, or property damage if performed incorrectly. Always hire a licensed electrician for electrical work, especially for service upgrades, panel work, and 240V circuits. Values are derived from NFPA 70 (NEC) for educational purposes. Always verify against your locally adopted NEC edition and amendments - local jurisdictions may enforce stricter requirements. WireRef provides reference information only and is not responsible for work performed based on this content. NEC® is a registered trademark of the National Fire Protection Association. Free NEC access via NFPA · OSHA Electrical Safety · Terms of use.
NEC 2023 references verified April 2026