new load center; fire rated wall Q.


Old 10-13-05, 01:48 PM
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new load center; fire rated wall Q.

I'm getting built a new, attached garage. There is to be a 1 hr fire rated wall adjacent to living areas, as I read the Code. In one of these walls, I intend to place a flush 200amp load center. Clearly, the sq. in. of a load center will exceed the max spec of an opening. The wall, will be a 6" stud framed, 5/8" drywall. What are my options to preserve the fire rating of this wall?
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Old 10-13-05, 01:51 PM
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Surface mount the box?
Old 10-13-05, 02:09 PM
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... or put the panel in a different wall.

Or if flush mount is important, build a second wall in front of the first.

You also might ask your inspector if it's okay to put two layers of 5/8" Type X drywall on the interior. That might provide the fire rating so that you can flush mount the panel on the garage side.
Old 10-13-05, 02:13 PM
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I could surface mount this 42 ckt box on drywall, but am aiming for something a bit more elegant. I've got a 1 1/2" main feed coming up from a poured slab that i'd rather keep inside the wall. Also, working with NM cable and clamps out the backside of the box thru drywall isn't appealing. I have seen some pourable wall fill that is used in fire rated walls. Is that ever used in residences?
Old 10-13-05, 02:38 PM
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Unlike electrical code, building code tends to vary a lot by region of the country so I think the best resource you will have is your local building department.

I would consider surface mounting the box and install a number of 1/2" or 3/4" EMT conduits from the box up to the attic to run your Romex into the box. That way you will not have a bunch of exposed Romex above the box, and you can paint the conduit to match the wall for a clean "industrial" look.
Old 10-13-05, 04:06 PM
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Assuming this is a single-family home...unless you have a local code/ordinance, generally the model fire and building codes don't actually require a 1-hour rated wall between the garage and living space. They normally specify a minimum of 1/2-inch drywall and a 20-minute steel or 1-3/4 inch thick solid wood door. Similar but not actually 1-hour fire rated construction.

I would check with your inspector and see if you can put the required drywall behind the panel. Or... the surface mount option is still there.


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