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PVC Round Ceiling Box 20 cu.in.

PVC ceiling box for light fixtures and ceiling fans.

20

cu.in. Volume

10

Max 14 AWG

9

Max 12 AWG

4" Round x 2-1/4"

Dimensions

Conductor Capacity per NEC 314.16

Maximum number of conductors that can fit in this 20 cu.in. box based on wire gauge (not accounting for devices, clamps, or grounds).

Wire GaugeVolume EachMax Conductors*
18 AWG1.5 cu.in.13
16 AWG1.75 cu.in.11
14 AWG2 cu.in.10
12 AWG2.25 cu.in.8
10 AWG2.5 cu.in.8
8 AWG3 cu.in.6
6 AWG5 cu.in.4

*Theoretical maximum for conductors only. Actual capacity will be less when including devices, clamps, and grounding conductors.

Common Applications

Ceiling lights
Ceiling fan mounts
Pendant lights

Calculate Box Fill for PVC Round Ceiling Box 20 cu.in.

Use our free calculator to verify your PVC Round Ceiling Box 20 cu.in. meets NEC 314.16 requirements.

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Similar Box Types

4" Square x 1-1/4" Deep

4" x 4" x 1-1/4" • 18 cu.in.

4" Square x 1-1/2" Deep

4" x 4" x 1-1/2" • 21 cu.in.

4-11/16" Square x 1-1/4" Deep

4-11/16" x 4-11/16" x 1-1/4" • 25.5 cu.in.

4-11/16" Square x 1-1/2" Deep

4-11/16" x 4-11/16" x 1-1/2" • 29.5 cu.in.

About the PVC Round Ceiling Box 20 cu.in.

The PVC Round Ceiling Box 20 cu.in. provides 20 cubic inches of volume for electrical connections. This pvc box is commonly used for ceiling lights, ceiling fan mounts, pendant lights. With dimensions of 4" Round x 2-1/4", it offers adequate space for most residential and light commercial applications.

Box Fill Calculation Example

For a typical installation using 14 AWG conductors:

  • Box volume: 20 cu.in.
  • 14 AWG conductor volume: 2.00 cu.in. each
  • Maximum conductors (theoretical): 10

Remember to account for devices (2× conductor volume each), internal clamps (1× conductor volume), and equipment grounding conductors (1× conductor volume for all grounds combined).

Practical Example: Receptacle Installation

Installing a duplex receptacle with two 14/2 NM cables in this box:

  • 4 × 14 AWG conductors = 4 × 2.00 = 8.00 cu.in.
  • 2 × grounds (count as 1) = 1 × 2.00 = 2.00 cu.in.
  • Internal clamps = 1 × 2.00 = 2.00 cu.in.
  • 1 × receptacle = 2 × 2.00 = 4.00 cu.in.
  • Total: 16.00 cu.in.

Result: 16.00 cu.in. ≤ 20 cu.in. = COMPLIANT

Related Resources

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