Q. Is the electrical wiring system used to feed ceiling fixtures allowed to be supported by the ceiling support wires?
A. No. Raceways, cable assemblies, boxes, cabinets, and fittings must be securely fastened in place. The ceiling-support wires or ceiling grid must not be used to support raceways and cables (power, signaling, or communications). However, independent support wires that are secured at both ends and provide secure support are permitted [300.11(A)].
Outlet boxes [314.23(D)] and luminaires can be secured to the suspended-ceiling grid if securely fastened to the ceiling-framing members by mechanical means, such as bolts, screws, or rivets — or by the use of clips or other securing means identified for use with the type of ceiling-framing member(s) used [410.36(B)].