Conference room projector
What's wrong here?
- The projector cord runs up through a hole cut in the ceiling tile
- A receptacle outlet is never permitted above a lay-in suspended ceiling
- The projector needs its own dedicated 20 A branch circuit
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
The projector's flexible power cord runs through a hole in the suspended ceiling and plugs in above it.
Correct choice: 1. The projector cord runs up through a hole cut in the ceiling tile
400.12 prohibits flexible cords from being run through holes in suspended or dropped ceilings (400.12(2)) and from being located above suspended or dropped ceilings (400.12(5)). A cord above the tiles is out of sight, gets crushed or chafed by tile and grid work, and is often in an air-handling space where a cord jacket adds fuel and smoke. This is one of the most common AV-install misses in commercial tenant spaces, because it looks tidy from the floor.
How to fix it
Install a receptacle outlet at the projector, for example a box supported from the structure with the receptacle at the tile face, or a projector mount with an integral listed receptacle box, fed with a Chapter 3 wiring method. The projector cord then plugs in below the ceiling.
Code references
NEC 2023 400.12(5) — Uses Not Permitted
Flexible cords and cables shall not be concealed by walls, floors, or ceilings, or located above suspended or dropped ceilings. An exception permits them inside an enclosure in other spaces used for environmental air as allowed by 300.22(C)(3).
Drills citing 400.12(5)NEC 2023 400.12(2) — Uses Not Permitted
Flexible cords and cables shall not be run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors.
Drills citing 400.12(2)NEC 2023 314.29 — Boxes, Conduit Bodies, and Handhole Enclosures to Be Accessible
Boxes shall be installed so that the wiring contained in them can be rendered accessible without removing any part of the building or structure.
Drills citing 314.29
2026 NEC:same rule and number. No 2026 change to 400.12 was found: cords still may not be run through holes in suspended ceilings (item 2) or sit above suspended or dropped ceilings (item 5). The existing exception for cords in an enclosure in other spaces used for environmental air carries over. Confidence: medium
Minnesota
Minnesota adopted the 2023 NEC without amendment as the Minnesota Electrical Code (Minn. Rules 1315.0200; Minn. Stat. 326B.35), effective July 1, 2023, so 400.12 applies as published. That edition governs permits filed through Aug. 16, 2026; permits filed on or after Aug. 17, 2026 fall under the 2026 NEC; see the 2026 NEC note on this drill for how the cited section fares there.
How Minnesota adopts the NECWhy the other choices are wrong
- A receptacle outlet is never permitted above a lay-in suspended ceiling. Boxes and receptacles above a lay-in ceiling are permitted when the wiring can be reached by lifting a removable tile (314.29). The problem is the flexible cord going up there, not the receptacle.
- The projector needs its own dedicated 20 A branch circuit. No NEC rule requires a dedicated circuit for a projector; a general-purpose circuit with capacity is fine.
- Nothing. This installation is compliant. Flexible cord may not run through holes in a suspended ceiling or be located above it (400.12(2) and (5)).