pvc Box
Old Work Box 1-Gang 18 cu.in.
Larger cut-in box for retrofit installations with more conductors.
Quick answer
A Old Work Box 1-Gang 18 cu.in. (18 cu.in.) holds 8 × 12 AWG or 9 × 14 AWG conductors in a bare box under NEC 314.16.
Subtract two allowances for each device or strap, and one for each set of internal clamps, grounding conductors, or support fittings. Run your exact box fill →
18
cu.in. Volume
9
Max 14 AWG
8
Max 12 AWG
3" x 2" x 3-1/2"
Dimensions
Conductor Capacity per NEC 314.16
Maximum number of conductors that can fit in this box based on wire gauge (not accounting for devices, clamps, or grounds).
| Wire Gauge | Volume Each | Max Conductors* |
|---|---|---|
| 18 AWG | 1.5 cu.in. | 12 |
| 16 AWG | 1.75 cu.in. | 10 |
| 14 AWG | 2 cu.in. | 9 |
| 12 AWG | 2.25 cu.in. | 8 |
| 10 AWG | 2.5 cu.in. | 7 |
| 8 AWG | 3 cu.in. | 6 |
| 6 AWG | 5 cu.in. | 3 |
*Theoretical maximum for conductors only. Actual capacity will be less when including devices, clamps, and grounding conductors.
Common Applications
Complex remodel wiring
Multiple circuit retrofits
Calculate Box Fill
Use our free calculator to verify NEC 314.16 requirements.
Calculate Box Fill