NEC · 2020 National Electrical Code
§314.16 · Box fill
Effective in NEC 2020 · NEC 2023 NW Indiana.
Plain-English explainer
314.16 (box fill): the number of conductors, devices, clamps, fittings, and EGCs in a box is counted per 314.16(B) and the resulting volume in cubic inches selects a box from Table 314.16(B). No box is overfilled, and every device or splice is enclosed by an approved cover or closure.
Why inspectors flag this
An undersized box on a kitchen-circuit rough-in is a top-3 314.16 red-tag; the drafter lifts the rule so the layout carries the right box size for the conductor count.
As quoted in the code: The number of conductors, devices, clamps, fittings, and equipment grounding conductors in a box is counted per 314.16(B), and the resulting volume in cubic inches selects a box from Table 314.16(B); no box is overfilled, and every device or splice is enclosed by an approved cover or closure.
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