Supporting wiring above suspended ceilings

What the code requires

Above a suspended ceiling, ceiling support wires that do not give secure support may not be the only support for cables, raceways or boxes. Independent support wires added with fittings may be used if they are secured at both ends. No cable or raceway may be supported by the ceiling grid itself.

In a fire-rated ceiling assembly, wiring in the cavity may not be fastened to the ceiling assembly or its support wires. Independent supports may attach to the assembly, and the added support wires must be distinguishable from the rated design, for example by color or tagging. Non-fire-rated ceilings follow the same rules, and the added wires must also be distinguishable.

A raceway may support other items only if it is identified for support, if it carries power to equipment and supports that equipment's Class 2 or Class 3 control wiring, or if it supports boxes or conduit bodies under 314.23 or luminaires under 410.36(E). Cables may not support other cables, raceways or nonelectrical equipment.

On the job

• MC cable or raceway tied to ceiling grid wires or T-bar is a common correction.
• Data cable strapped to an EMT run is a common fail.

Exceptions that matter

• In fire-rated ceilings, assemblies that were tested with the wiring in place are an exception.
• In non-fire-rated ceilings, the ceiling system may support branch-circuit wiring if the ceiling manufacturer's instructions allow it.

What changed in 2023

The 2023 edition added Class 3 control wiring to what a raceway carrying power to equipment may support.

Related sections

• NEC 300.11(A)
• NEC 314.23
• NEC 410.36
• NEC 334.30: Stapling and supporting NM cable

Where this comes from

• NFPA: 2026-cycle CMP-3 First Draft ballot (2023 baseline text)
• NFPA: 2023-cycle CMP-3 First Draft ballot (FR 9230)
• Read the official NEC free at NFPA