Cable Ampacity Chart (NEC Table 310.16)
Allowable ampacities for insulated conductors per NEC Table 310.16, copper and aluminium, in the 60 °C, 75 °C and 90 °C columns.
| AWG / kcmil | Cu 60°C | Cu 75°C | Cu 90°C | Al 60°C | Al 75°C | Al 90°C |
|---|
Standard: NFPA 70 (NEC) Table 310.16, 2023 · Data checked: 2026-10-14
Frequently asked questions
Which temperature column should I use — 60, 75 or 90 degrees C?
The lowest rating in the circuit, which is almost always the termination, not the conductor. Most terminations are rated 75 degrees C, so the 75 degree C column is the usual answer even when the wire itself is 90 degree C rated — that is NEC 110.14(C) and it is why the 75 column is highlighted here.
Do I have to derate these numbers?
Yes. The table assumes no more than three current-carrying conductors in the raceway and an ambient temperature of 30 degrees C. More conductors in a bundle need a bundle adjustment factor; a hotter ambient needs a temperature correction factor. Both sets of factors are on the table page.
Why is aluminium lower than copper?
Aluminium has about 61% of the conductivity of copper for the same cross-section, so it heats up more for a given current and its allowable ampacity is lower. It is common in service entrance and feeder work but rarely used for branch circuits.
Can I use the 90 degree C column because my wire is rated 90?
Only if the terminations are also rated 90 degrees C, which they usually are not. Choosing the 90 column while the breaker lugs are 75 rated is one of the classic NEC violations, and it shows up as hot terminations rather than an immediate failure.