4" Octagon Box 1-1/2" Deep
Standard 4-inch octagon electrical box with 1-1/2 inch depth. Popular choice for ceiling mounted fixtures and junction points.
Quick answer
A 4" Octagon Box 1-1/2" Deep (15.5 cu.in.) holds 6 × 12 AWG or 7 × 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 →
15.5
cu.in. Volume
7
Max 14 AWG
6
Max 12 AWG
4" Octagon x 1-1/2"
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. | 10 |
| 16 AWG | 1.75 cu.in. | 8 |
| 14 AWG | 2 cu.in. | 7 |
| 12 AWG | 2.25 cu.in. | 6 |
| 10 AWG | 2.5 cu.in. | 6 |
| 8 AWG | 3 cu.in. | 5 |
| 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
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