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Electrical Box Fill Calculator — NEC 314.16 Volume Check

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NEC edition Use the edition adopted by the authority having jurisdiction.Available box volume (in³) Use marked/listed volume plus only valid marked extension/ring volume.#18 AWG counted conductors #16 AWG counted conductors #14 AWG counted conductors #12 AWG counted conductors #10 AWG counted conductors #8 AWG counted conductors #6 AWG counted conductors Internal clamp set present (0 or 1) Support fitting set/type present (0 or 1) Largest conductor for clamp/support allowance Device yokes / straps Largest conductor connected to entered yokes Entering equipment grounding conductors Largest entering EGC size Terminal-block assemblies (2023 only) Enter 0 for 2017/2020.

Calculated result

16 in³ required

PASS — box volume meets or exceeds calculated fill

Required: 16 in³ (262.2 cm³)

Available: 18 in³ · 88.9% used

Spare / deficit: 2 in³

Conductors: 8 in³ · devices: 4 in³ · grounds: 2 in³

Clamps/support: 2 in³ · terminal blocks: 0 in³

Show the working

1. 4 × #14 allowance 2.00 in³ = 8 in³.
2. Device yokes: 1 × 2 × 2.00 = 4 in³.
3. Equipment grounds: 2 → 1 allowance(s) × 2.00 = 2 in³.
4. Total required = 16 in³; 18 − 16 = 2 in³ spare/deficit.

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