Wire Gauge Box Fill Reference
Find conductor volume allowances by AWG size for NEC 314.16 box fill calculations. Select a wire gauge for detailed information.
AWG
Volume: 1.5 cu.in.
Max Ampacity: 7A
18 AWG conductors are typically used for low-voltage applications and control wiring.
AWG
Volume: 1.75 cu.in.
Max Ampacity: 10A
16 AWG conductors are used for light-duty circuits and appliance cords.
AWG
Volume: 2 cu.in.
Max Ampacity: 15A
14 AWG is the minimum size for standard 15-amp household circuits per NEC.
AWG
Volume: 2.25 cu.in.
Max Ampacity: 20A
12 AWG conductors are required for 20-amp circuits and kitchen/bathroom outlets.
AWG
Volume: 2.5 cu.in.
Max Ampacity: 30A
10 AWG conductors are used for 30-amp circuits such as dryers and water heaters.
AWG
Volume: 3 cu.in.
Max Ampacity: 40A
8 AWG conductors support 40-amp circuits for ranges and large appliances.
AWG
Volume: 5 cu.in.
Max Ampacity: 55A
6 AWG conductors are used for 55-amp circuits and sub-panel feeders.
NEC Table 314.16(B) Quick Reference
| AWG | Volume (cu.in.) | Volume (mm3) | Ampacity | Common Uses |
|---|---|---|---|---|
| 18 AWG | 1.5 | 24.6 | 7A | Thermostat wiring, Doorbell circuits |
| 16 AWG | 1.75 | 28.7 | 10A | Extension cords, Light fixtures |
| 14 AWG | 2 | 32.8 | 15A | 15-amp circuits, Lighting circuits |
| 12 AWG | 2.25 | 36.9 | 20A | 20-amp circuits, Kitchen outlets |
| 10 AWG | 2.5 | 41 | 30A | 30-amp circuits, Electric dryers |
| 8 AWG | 3 | 49.2 | 40A | 40-amp circuits, Electric ranges |
| 6 AWG | 5 | 82 | 55A | 55-amp circuits, Sub-panel feeders |