Doggone I wish they’d buy me a code book
jrnbj
| Posted in Energy, Heating & Insulation on
on the road again, overseeing the remodeling of some hotel meeting rooms….we’ve got millwork coming in that will have sconce(s) mounted to it…..
can I just poke a bx cable whip through a small hole in the double drywall fire wall, & then use a cut in box into the millwork when it gets here?…
Replies
We do that with pancake 1/2" deep boxes all the time, but I can't say whether it is code or not. being on an island doing remo work has it's advantages. But it seems to meet the needs in a logical fashion.
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Thanks Piffin...I don't want to mount the pancake boxes in the firewall because it's so deep (it's a layer of sound insulating fiberboard followed by 2 layers of 5/8 rock) and because I want to locate the sconces very prcisly in the yet to be built millwork...whips & old work boxes seemed the best bet...do it all the time w/undercounter lights -shouldn't they be called overcounter lights!-, but this is commercial hospitality, in Ft. Lauderdale, and they tell me the inspector here makes them run LV (Telcom cable) in conduit!
You could but likely you would exceed the cubic inch requirements demanded by the wires and device. Also trying to stuff wires into a 1/2" deep box is a PITA.
Better course would be to install a 2 hour fire rated old-work box. Usually either Bakelite or fiberglass and resin. Look closely att the boxes. Some have the fire rating pressed into the body and you may need to get them at an electrical supply house. Likely they have them in stock but if not they can order them.
These usually meet most fire wall requirements but if you need a higher rating you can wrap them in a layer, or layers, of fireblock, intumescent, sheet putty and achieve any rating required.
Of course if the box itself will cover the rating of the wall you need to pack the wall to box connection and where the cables, if applicable, come into the box with fire code caulk or putty.
Some inspectors also prefer to see either metal or Bakelite box covers instead of thermoplastic or nylon. On any boxes that are on a fire rated wall assembly. At least one wanted the receptacles themselves to be thermoset plastic, Bakelite being the most common, or ceramic.
usually i will locate where ty=he lite will be and leave a whip behind the wall so at finish i can hole saw for a box in exactly the right location reach in grab the wire mount the box and terminate
works great berg