Electrical wiring within the cavity of a fire-rated floor-ceiling or roof-ceiling assembly shall not be supported by the ceiling assembly or ceiling support wires.

• A. True
• B. False
• C. Sometimes
• D. Not specified

Answer: (A)

Wiring in a fire-rated cavity must be supported independently of the ceiling assembly. The fire rating of the floor-ceiling or roof-ceiling assembly relies on the integrity of that barrier and any attachments or supports that are tied into it can become weak points under high heat. If conductors are hung off the ceiling itself or its support wires, movement, sagging, or failure of the ceiling materials during a fire could compromise the barrier and potentially create a path for flame or smoke to bypass the rating. The safe practice is to use independent supports—listed clamps or staples attached to structural framing on either side of the assembly—that secure the wiring without relying on the ceiling assembly. After passing through the fire-rated boundary, firestop materials and proper sealing are still required to maintain the rating. Therefore, the statement is true.