Smoke detectors in ceiling tile - NEC 300.11(B)

[westgbazo]

I have an existing installation of smoke detectors in a suspended ceiling. The detectors are currently mounted directly to the ceiling tile. We are replacing the smoke detectors and the plan is to add a caddy bar/t-bar box hanger to attach the junction box and smoke detector from.

Does this assembly need to be supported independently of the ceiling grid, like shown in the picture below?



NEC 300.11(B) says "Cables and raceways shall not be supported by ceiling grids."

Since the junction box attached to the box hanger is not a raceway, I do not think we need the independent support wire. Thoughts?

Thanks in advance for your time and replies!

 

[gadfly56]

I have an existing installation of smoke detectors in a suspended ceiling. The detectors are currently mounted directly to the ceiling tile. We are replacing the smoke detectors and the plan is to add a caddy bar/t-bar box hanger to attach the junction box and smoke detector from.

Does this assembly need to be supported independently of the ceiling grid, like shown in the picture below?

View attachment 2565195

NEC 300.11(B) says "Cables and raceways shall not be supported by ceiling grids."

Since the junction box attached to the box hanger is not a raceway, I do not think we need the independent support wire. Thoughts?

Thanks in advance for your time and replies!

While I think you might be technically correct, I think more often than not, the AHJ will flag it if you don't have those independent support wires.

Consider the reason for the requirement regarding support wires. It's to protect the firemen if they have to open the ceiling from below looking for the fire, so they don't get a whole tumble of equipment and cable in their faces.