NEC Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Current is measured in amps. You must use the correct size wire for the current (load) requirement of the circuit to prevent the wire from overheating.

Wire Gauge Size
Copper Aluminum
60˚ C
(140˚) F
75˚ C
(167˚) F
90˚ C
(194˚) F
75˚ C
(167˚) F
90˚ C
(194˚) F
NM-B THW THWN-2 THW XHHW-2
UF-B THWN THHN THWN THHN
SE XHHW-2 SE TWHN-2
USE USE
XHHW XHHW
14152025
122025302025
103035403035
84050554045
65565755055
47085956575
3851001157585
29511513090100
1130145100115
1/0150170120135
2/0175195135150
3/0200225155175
4/0230260180205
250255290205230
300285320230260
350310350250280
500380430310350
600420475340385
750475535385435
1000545615445500