ECN Forum Forums Code Related Discussion NEC & other Code issues Common wall on condo

The firewall between townhouses in this area are commonly constructed of coreboard drywall set in "H" channel with resiliant firring screwed to it on both sides, some thin insulation, and 5/8" firecode drywall applied to that. There is no cavity for the boxes. So builders usually stretch the 12 ft. limit on the front and rear wall of the room or add a floor box. We are told "no penetrations" are to be made to the rated wall. Even the floor joists are run parallel to the wall without attachment to the rated wall.

I've only worked on something similar to this once, and that was an apartment complex rewire.. Shared walls got 4S boxes (or 1900's for you east coasters ) with a 3M pad. All of our NM-B's passing into or through the wall had to be sleeved in FMC with Firestop caulking around the wall penetration. ¾" drywall was used on shared walls as well

Very interesting responses. Unfortunately, I had already put in a switch on this wall to two recessed cans I installed. I did notice that there was an outlet on the floor in the middle of the wall. Any suggestions on what I can do at this point? I used a regular cut-in blue box for the switch. Everything in the condo is pulled in romex as expected.

Thanks

As I understand it, given a 1 hr rated wall, then the deal is:
If it is a steel box 16 sq inches or less and there are not more than 100 sq inches combined total of openings in 100 square feet of wall, then it does not need a fire pad as fill for the annular space.
PROVIDED:
1)Outlet boxes on the opposite side have a separation horizontally of not less than 24".
or
2) It's got solid fire blocking in between the boxes on the opposite side
or
3)If it's got loose fill cellulose or mineral fiber insulation, it can have a horizontal separation not less than the depth of the wall cavity from a box on the opposite side.
or
4) It's a box made of any material.listed and tested for the purpose.

If the rating is greater than 1 hr, or it 1hr and doesn't meet the requirements above, then you'll have to firepad a metal box.

If you've put in a cut-in box, or Madison clipped it a box, steel or not, it has to come out.
Boxes in fire-rated walls can't be supported by the drywall.

A regular blue plastic box won't do, regardless.

It's good to see some concern over this important subject of fire ratings. Too many guys don't even notice, or just don't care.

If your floor outlet is within 18" of the wall, then it can be counted as one of the required outlets. 210.52(A)(3) Unfortunately, if you have a 15 foot wall, a minimum of 2 would be required.



[This message has been edited by electure (edited 12-09-2006).]

Check this UL article:
http://www.ul.com/regulators/sepoct2000.pdf

HLCbuild, in my townhouse (in Manassas) they did provide a cavity for boxes, there is the party wall which is as you described, but there are studs and another layer of drywall. They also put insulation in the wall, too, believe it or not. Incidentally, the party wall is attached to the framing of the house with metal "L" brackets which I'm told will melt in the event of a fire, preventing the party wall from being pulled down.

Apparently it works pretty well since the townhouse across the street caught fire and pretty much had to be torn all the way down. The party wall on either side was still intact.