All About Circuits
Volume 
EE Reference
Chapter
Conductor and Insulator Tables
PDF Version

Copper Wire Ampacity Table



Ampacities of copper wire, in free air at 30o C:

INSULATION TYPE
  RUW, T THW, THWN FEP, FEPB
  TW RUH THHN, XHHW
Size Current Rating Current Rating Current Rating
AWG @ 60 degrees C @ 75 degrees C @90 degrees C
20 *9 ----- *12.5
18 *13 ----- 18
16 *18 ----- 24
14 25 30 35
12 30 35 40
10 40 50 55
8 60 70 80
6 80 95 105
4 105 125 140
2 140 170 190
1 165 195 220
1/10 195 230 260
2/0 225 265 300
3/0 260 310 350
4/0 300 360 405

* = estimated values; normally, wire gages this small are not manufactured with these insulation types. 

 

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  • Leharos September 08, 2025

    The table values do not look good to me—too big. I am used to NEC Table 310.15(b)(16) .

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