Wire Size Chart (Ampacity by AWG)

Pick material and termination rating — the chart shows the ampacity your conditions actually allow.

Reading the chart right

Values are consistent with NEC 310.16 for 30°C ambient and no more than three current-carrying conductors. Two rules catch people: terminations govern — 90°C wire on a 75°C breaker lug is a 75°C circuit; and 240.4(D) caps 14/12/10 AWG copper at 15/20/30 A breakers regardless of the column. The third column shows that cap where it applies.