Ceiling Fan support

[Paul Johnston]

Does anyone have pictures or drawings of the proper or accepted way of mounting electrical boxes for ceiling fans when the ceiling is framed with metal for drywall installation?
Thanks
Paul

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[John Dirks Jr]

This is just off the top of my head. Could you fix lengths of 2x4s to the steel studs with screws and then mount the traditional fan bracket to the wood?

[Markus Keller]

For a standard ceiling fan all you really need is a hanger bar attached to the 1900 box to span from joist to joist. With the hanger bar the box/fan has support across both sides. If the box is just attached to the side of one joist, the weight can slowly pull the other side of the box down through the ceiling. They also make a heavy duty bar for bigger fans and a remod bar. Using a 2x4 doesn't generally work too well because it restricts your ability to run lines into the box.

[Jerry Peck]

Marcus,

The problem, or concern, is (I think) the use of the metal drywall studs for ceiling joists.

They are not rated to carry loads that way, and adding gypsum board to them is bad enough, hanging a ceiling fan from them is just asking for trouble.

The ceiling fan box should be mounted from wood joists laid across the metal framing, as John said, only I would recommend a long 2x6, long enough to carry the weight across several of those metal studs (so there is no visual deflection in the ceiling where the weight is distributed to), then, the entire assembly around the ceiling fan (or at least the ceiling fan support itself - the 2x6) be supported from above to either a structural ceiling above or to the trusses above.

I *would not* rely only on the metal stud framing to securely support the drywall and the ceiling fan.

From the 2008 NEC.
- 314.27 Outlet Boxes.
- - (D) Boxes at Ceiling-Suspended (Paddle) Fan Outlets. Outlet boxes or outlet box systems used as the sole support of a ceiling-suspended (paddle) fan shall be listed, shall be marked by their manufacturer as suitable for this purpose, and shall not support ceiling-suspended (paddle) fans that weigh more than 32 kg (70 lb). For outlet boxes or outlet box systems designed to support ceiling-suspended (paddle) fans that weigh more than 16 kg (35 lb), the required marking shall include the maximum weight to be supported.

- 110.3 Examination, Identification, Installation, and Use of Equipment.
- - (B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

Between the two above, it addresses it. If only that the box shall be installed in accordance with its listing and labeling, and, if not listed and labeled for that use (supported from that metal framing) it is not allowed to be used that way. I doubt that the installation instructions for the box addresses it being used that way, and, if not, then it probably shows it mounted to wood, in which case you get back to 'properly securing the wood support up to the structure', with the wood support being that 2x6 laid across the metal framing.

Just my half pence worth.

[Jerry McCarthy]

Interesting question, I've never seen anything on paddle fan support requirements from metal ceiling joist?
2005 NEC Articles 314.27 and 422.18 address wood framing, but there is nothing on metal. Nothing in the 2008 NEC either? Hello 2011 NEC Code Adoption?

[Jerry Peck]

WC Jerry,

They don't really address "wood" framing, but 'structural' framing, which could be metal, if the metal were "structural" rated and sufficiently strong enough to support the ceiling fan.

The problem with that metal framing, described as "framed with metal for drywall installation" is that the studs are not intended for "structural" loads, only those loads applied by the weight of the gypsum board as accessory items (wall lights, pictures, mirrors, etc.). Those would be 25 gage metal studs ... metal "studs" being key - not sure exactly what they are rated for when installed horizontally as "joists".

Typically, "structural" metal studs will be from start at 20 gage and go to 16 gage.

Metal "joists" are likely going to be larger (equivalent to 2x6 or larger) and likely going to be heavier gage (probably 20 gage).

With the correct metal framing, it would be "structural" and would be strong enough within itself.

All the above meaning ... I doubt the NEC will address it as 'the type of material used for support' is not specified by the NEC.

[Markus Keller]

If my brain were twice as large I'd have half a useful brain.
Jerry, I never even registered the metal ceiling framing. That does change the scenario substantially.
If they used light gauge studs (non-struc wall) or if it's a dropped ceiling, then spanning several joists with wood would be helpful. I would also suggest running 2 straps to the structure above the ceiling (the concrete?) to hold the ceiling from sagging down.
If they used structural members, then mount as necessary.