NEC Wire Size Chart 2026 — Complete Ampacity Table NEC Table 310.16 Reference
NEC Table 310.16 is the most referenced table in the National Electrical Code. It provides ampacity ratings for copper and aluminum conductors at three temperature ratings: 60°C, 75°C, and 90°C. This guide presents the complete table with explanations of when to use each column, derating factors, and practical wire sizing examples.
NEC Table 310.16 — Complete Wire Size Chart
This table applies to not more than 3 current-carrying conductors in raceway, cable, or earth (directly buried). For 60°C column: use with NM-B (Romex), UF-B, and most residential cable. For 75°C column: use with THWN, XHHW, and wire in conduit when terminals are rated 75°C. For 90°C column: use with THWN-2, XHHW-2 — but ampacity is limited by the termination temperature rating per NEC 110.14(C).
When to Use Each Temperature Column
60°C column: NM-B cable in residential work. Per NEC 334.80, NM-B ampacity is determined by the 60°C column even though the insulation is rated 90°C. 75°C column: THWN wire in conduit when breakers and devices have 75°C-rated terminals (most modern equipment). This is the most commonly used column in commercial work. 90°C column: Used only for ampacity derating calculations. After applying derating, the final ampacity cannot exceed the 75°C (or 60°C) value per NEC 110.14(C).
Ampacity Derating: When to Reduce Wire Capacity
More than 3 conductors: NEC 310.15(C)(1) requires derating when more than 3 current-carrying conductors are bundled. 4-6 conductors: 80% of table value. 7-9: 70%. 10-20: 50%. This is where the 90°C column becomes useful — start with the higher ampacity, apply the derating percentage, and the result must not exceed the termination temperature column. High ambient temperature: NEC 310.15(B)(1) provides correction factors for temperatures above 86°F (30°C). For example, at 104°F (40°C), the 75°C column factor is 0.88.
Aluminum vs Copper: Key Differences
Aluminum wire has roughly 61% the conductivity of copper, so it requires larger wire for the same ampacity. For example, 1 AWG copper (130A at 75°C) is equivalent to 1/0 AWG aluminum (120A at 75°C). Aluminum is significantly cheaper for large sizes and commonly used for service entrance cables, sub-panel feeders, and utility drops. All aluminum connections must use AL/CU-rated devices, anti-oxidant compound, and be torqued to specification.
| AWG/kcmil | 60C (NM-B) | 75C (THWN) | 90C (THWN-2) |
|---|---|---|---|
| 14 AWG | 15A | 20A | 25A |
| 12 AWG | 20A | 25A | 30A |
| 10 AWG | 30A | 35A | 40A |
| 8 AWG | 40A | 50A | 55A |
| 6 AWG | 55A | 65A | 75A |
| 4 AWG | 70A | 85A | 95A |
| 3 AWG | 85A | 100A | 115A |
| 2 AWG | 95A | 115A | 130A |
| 1 AWG | 110A | 130A | 145A |
| 1/0 | 125A | 150A | 170A |
| 2/0 | 145A | 175A | 195A |
| 3/0 | 165A | 200A | 225A |
| 4/0 | 195A | 230A | 260A |
Common Wire Sizing Examples
15A circuit: 14 AWG copper (15A at 60°C). Standard lighting and general receptacle circuits. 20A circuit: 12 AWG copper (20A at 60°C). Kitchen, bathroom, and laundry circuits per NEC 210.11(C). 30A circuit: 10 AWG copper (30A at 60°C). Electric dryer (NEMA 14-30). 50A circuit: 6 AWG copper (55A at 60°C). Electric range, EV charger. 100A sub-panel: 1 AWG copper or 1/0 aluminum. 200A service: 2/0 copper or 4/0 aluminum. Use our Wire Size Calculator for exact sizing.
Disclaimer: For educational reference only. Consult a licensed professional.