300-11. Securing & Supporting

A) Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place. Support wires that do not provide secure support shall not be permitted as the sole support.

1) Wiring located above a fire-rated floor/ceiling or roof/ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided.

2) Wiring located above a non-fire-rated floor/ ceiling or roof/ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided. Cables and raceways shall not be permitted to be supported by ceiling grids.

NEC Article 300.11 addresses the issues of securing and supporting. Cables and raceways must have their own support—independent of other systems. Their supporting structures cannot be piggybacked onto other supports. For example, you can’t hang conduit from ceiling grids, but you can clamp to the I-beams or rafters to hang rod and strut specifically for the conduit. (C) prohibits using wireways to support other wireways, cables, or non-electrical equipment. Thus, using cable ties to secure the wiring for that new PA system to conduit is a Code violation. A chief concern of NEC Article 300.11 is that electrical wireways be independent. They may share a support—for example, you can strap multiple conduits to a strut suspended by two rods. But, you cannot then strap a strut to those conduits and hang a secondary set of rods to support another set of conduit or anything else.