30 AWG wire size
0.255 mm · 0.051 mm²
0.01 in diameter · 338.53 Ω/km in copper
What 30 AWG is used for
Wire-wrap and circuit-board repair wire — about the thickness of a hair on the coarse side.
The numbers
| Diameter | 0.255 mm · 0.01 in |
| Cross-sectional area | 0.0509 mm² |
| Resistance, copper | 338.53 Ω/km · 103.184 Ω per 1,000 ft |
| Resistance, aluminium | 553.744 Ω/km |
| NEC 60 °C copper ampacity | — outside the common building-wire range |
How 30 compares
The gauge scale is geometric, so the useful comparisons are ratios rather than differences. 24 AWG is twice the diameter, which is four times the area.
| Gauge | Diameter | Area | Ω/km copper | vs 30 |
|---|---|---|---|---|
| 24 | 0.511 mm | 0.205 mm² | 84.21 | 4.02× the area |
| 26 | 0.405 mm | 0.129 mm² | 133.9 | 2.53× the area |
| 28 | 0.321 mm | 0.081 mm² | 212.9 | 1.59× the area |
| 32 | 0.202 mm | 0.032 mm² | 538.28 | 0.63× the area |
| 34 | 0.16 mm | 0.02 mm² | 855.91 | 0.4× the area |
| 36 | 0.127 mm | 0.013 mm² | 1360.94 | 0.25× the area |
Frequently asked questions
What is 30 AWG in mm?
0.255 mm in diameter (0.01 inches), with a cross-sectional area of 0.051 mm².
Is 30 AWG used for power wiring?
Not for building circuits. It is a signal and low-current gauge — thinner than anything a domestic branch circuit uses.
What is the resistance of 30 AWG copper?
338.53 Ω per kilometre, or 103.184 Ω per 1,000 feet, for annealed copper at 20 °C. The same gauge in aluminium is about 553.74 Ω/km — 1.64 times higher, which is why aluminium wiring is sized larger for the same load.
Why do smaller AWG numbers mean thicker wire?
The number counts drawing operations. Wire is pulled through progressively smaller dies, and the gauge records how many passes it took — so more passes means a higher number and a thinner wire.