Centaur 4" Round Fan Support Box – 1-1/2" Deep with FB Side Mount Bracket per 4

The Centaur CM-FSB-FB 4 inch round box is fan rated, so it is built to carry a ceiling fan without a separate fan-rated brace kit. Support comes from the FB side mount bracket that ships with it, which fastens to the framing member beside the box. If your opening has no joist within reach of the bracket, you need a spanning brace bar instead, since this box is a side-mount design and not a between-joist expanding bar.

Depth is the thing to check here. The Centaur round fan support box is 1-1/2 inches deep and 4 inches in diameter, which is a shallow box by fan-box standards. That is fine for a straight fan or fixture hookup with a couple of conductors and a ground, but if you are landing several branch circuit runs plus the fan leads and a remote receiver module, you will be fighting for space. For remote-module installs, look for a deeper fan box.

Both, per Centaur. The 4 inch round fan support box is built for new construction and retrofit work alike. The deciding factor is access: the FB side mount bracket has to be fastened to a joist or framing member, so on a finished ceiling you need the drywall open or a joist directly at the hole. If you are cutting into closed drywall with no framing at the location, a retrofit expanding fan brace is the right call instead.

It is a non-metallic box. Since the enclosure itself is not a conductor, there is no bonding path through the box, so your equipment grounding conductor has to be carried through to the fixture ground on the fan mounting bracket. Contractors also like non-metallic here because there is nothing to corrode in damp attic or garage ceilings.

The FB style side mount bracket is included with the box, so you are not sourcing a bracket separately. What is not included is the fan itself or the fan's downrod canopy hardware, and you supply the wood screws or nails into the joist and the cable connectors for your wiring method.

Yes. A 4 inch round fan-rated box is rated above what a standard luminaire needs, so the Centaur box works for ordinary ceiling lights and as a general junction box as well. Property managers often standardize on the fan-rated version across a building so any unit can later take a ceiling fan without opening the ceiling again.

The Centaur 4 inch round fan support box with the FB side mount bracket is sold per 4, so one order gives you four boxes with their brackets. Worth knowing if you are rough-in framing several units at once.