| Property |
Value |
| Gauge 21 Diameter (in) |
0.0285 in |
| Gauge 21 Diameter (mm) |
0.723 mm |
| Gauge 21 Turns of Wire (per inch) |
35.1 turns/in |
| Gauge 21 Turns of Wire (per cm) |
13.8 turns/cm |
| Gauge 21 Cross-Sectional Area (kcmil) |
0.81 kcmil |
| Gauge 21 Cross-Sectional Area (mm²) |
0.41 mm² |
| Copper Resistance (Ω/km or mΩ/m) |
42.0 mΩ/m |
| Copper Resistance (Ω/kft or mΩ/ft) |
12.8 mΩ/ft |
| NEC Copper Wire Ampacity (60°C) |
0 A |
| NEC Copper Wire Ampacity (75°C) |
0 A |
| NEC Copper Wire Ampacity (90°C) |
0 A |
| Fusing Current (10 s) |
49.0 A |
| Fusing Current (1 s) |
125.0 A |
| Fusing Current (32 ms) |
700.0 A |
Frequently Asked Questions (FAQs) About 21 AWG Wire
What does AWG stand for?
AWG stands for American Wire Gauge, a standardized system for measuring wire sizes. The smaller the AWG number, the larger the wire diameter.
How does 21 AWG compare to 20 AWG?
21 AWG wire is smaller than 20 AWG, with a diameter of 0.723 mm compared to 0.812 mm for 20 AWG. It has the same ampacity (0 A at 90°C) but a smaller cross-sectional area and higher resistance.
What applications are suitable for 21 AWG wire?
21 AWG wire is typically used for extremely low-current applications, such as fine electronics, hobby projects, or small signal wiring, due to its limited ampacity.
What happens if the fusing current is exceeded?
If the fusing current is exceeded (e.g., 49 A for 10 seconds in 21 AWG), the wire will overheat and melt, potentially causing a fire hazard or circuit failure.
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