I am putting up acoustical ceiling, with grids and tiles. How is the smoke detector installed in such case? In a sheetrock ceiling, I would fasten the round box to be level with ceiling and all the wires would rest in it. In a drop ceiling, can I fasten the detector base to the grid and leave the detector wires open between the base and the box? Thank you to all in advance.
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residential or commercial?
Commercial has lots of rules about what can be above a suspended ceiling.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Upon careful introspection, I have deemed your query worthy of a definitive respone since you are so worthy.
There are two types of smoke [paint fume, dust] detectors: low voltage and regular. Most likely you have a regular 120 volt contraption, so I will gallently follow that course.
I am in the commercial end of the electrical business so I will stick to what I know. There is a commercial bar, ~24" long with clips at the extremities which clip to the grid bars. An example is made by B-Line. It comes with another clip and a 1/4"-20 screw and you knock the center hole out of the bottom of a metal box and put the tab of the clip through the hole and over the bar and screw it in place. Between these two adjustments, you can situate the box exactly where you want -- within limits. That is,id est, you can't get totally close to the grid bar.
Then you add a round 3/4"? mud or plaster ring. Use a 3 1/2" hole saw to drill a hole in your tile in the calculated spot. The smoke, dust, paint fume detector attaches to this mud ring.
It is important to run an additional grid support wire to the metal box from above. You can also use this grid wire to support your 12-3 or 14-3 cable coming out of your box with a batwing.
~Peter
Wanna bet he has no idea what a batwing is?
"Wanna bet he has no idea what a batwing is?"I know I haven't a clue.BruceT
I wish I knew enough to give you a link. Google "Caddy KX KON clip".
You will get a picture of the device that is used to support conduit or MC cable from a hanger wire or rod.
http://www.erico.com/products/CADDYcfcConduitHangers.asp.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks for the batwing link.
BruceT
You can also use this grid wire to support your 12-3 or 14-3 cable coming out of your box with a batwing.
You forgot to mention that it's really best to do this with the tile available, usually right as the minors are going in, so you can slide the hole-cut tile in without tearing too many of the edges up (since Murphy insists that it be a tegular tile job in a custom color, with grids of equally custom appearance that show dings for glancing at them wrong . . .)<G>Occupational hazard of my occupation not being around (sorry Bubba)
Actually.... no ceiling wire is permitted to support the weight of the control wires. Also an additional support wire is not needed is you are a using a caddy type fastener that attaches over the web of the main tee/ cross tee. You would need a slack support wire if it was a down light, but not for a simple J- box.Union acoustical installer,
Michael
I didn't need to imply that a ceiling grid support wire was permitted to support electrical cables. The grid wire I referred to would be a seperate wire solely for electrical support. [exception: if the manufacturer of the ceiling system specifically allows this. I've never heard of this happening.
It's not a matter of the ceiling support wires not being able to support the little extra weight, but that they will exert a sideways force which will in turn pull up the grid and make it unlevel.
I have never actually seen the code or regulations or specifications for this type of support but have learned from experience. Each job seems different. 2 screws and 4 wires; 4 screws and 2 wires, 4 screws and 4 wires. [for drop in lights] But it is better not to take chances with an inspection and adding a wire to a simple box is a small price to pay. That is why there is a built in hole of the bar clip.
There seems to be a minimum of 3 wraps or turns but does this have to occur close to this attachment point?I am able now to get nice, tight spirals.
All this is in case of a fire, the fireladies can pull down the stupid grid and not have the luminaires fall on their helmets. [What is the Stanford-Benet IQ of a ceiling tile?]
~Peter
Peter you are correct out here in L.A. City the inspectors are as tough as they get nearly OSPD/ DSA. teh bigger issue is when sparky ties up his BX cable or the data cable clowns pull their wires tight around the suspension wires causing the ceiling to lift. The all require "hospital" wraps on the wire. They do not require us to install wires on the J- box's or strobes.
Some require them on Down lights some do not. We do it regardless. Also HD rated grid much be used throughout now per IBC and LARR. 2 Wires and 4 screws per recessed fixture.ML
Thank you for your reply and sorry about my late response. In fact, though, and to answer BillHartmann's question, this is for one family house and basement renovation. Electric inspector has already approved the rough work. I had gone overboard and wired for 2 smoke detectors (to tie in with existing detector and one in the far corner and one near the exit) but was told I need just one.
I think I understand what has to be done for this. Even though this is residential work, I need to provide work box with a support between the grids and not have the detector wires in the air. Support the box with wire. This is based on observation that residential and commercial works have some common practice.
Again, thanks.