Electrical box location

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curtisd

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In a motel, each wall between the rooms are firerated. Can you have 2 receptaces in the same stud cavity that do not feed the same room. One serves one room and the other serves the adjoining room. Do they have to be in different stud cavities. The boxes are UL listed at 2hr fire rating if that makes any difference.
Thanks
 
Re: Electrical box location

I have looked in the NEC and can't find anything but the IBC does have something but I thought someone in here may be able to help. Thanks anyway.
 
Re: Electrical box location

Charlie's right its an IBC thing. See 2003 IBC 712. If you don't want to protect the box with fireproofing material, you have to separate them by a horizontal distance of 24". Even if there at different heights aff they still have to be >24" apart.

[ November 30, 2005, 02:00 PM: Message edited by: sceepe ]
 
Re: Electrical box location

MPD, IMO 300.21 is a waste of ink, the specifics are in other codes and standards, 300.21 doesn't say anything in reality.

From Volume One of the UL Fire Resistance Directory.

WALL AND PARTITION ASSEMBLIES

Metallic Eletrical Outlet Boxes

Listed single and double gang metallic outlet and switch boxes with metallic or nonmetalliccover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2h. These walls shall have gypsum wallboard facings similar to those shown in Design Nos. U301,U411, and U425. The metallic outlet or switch boxes shall be securely fastened to the studs and the opening in the wallboard facing shall be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes shall not exceed 16 sq in. The aggregate surface area of the boxes shall not exceed 100 sq in per 100 sq ft of wall surface.

Metallic boxes located on opposite sides of walls or partitions shall be seperated by a minimum horizontal distance of 24in. This minimum seperation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification.

Metallic boxes shall not be installed on opposite side of walls or partitions of staggered stud construction unless "Wall Opening Protective Materials" are installed according to the requirements of their Classification.

Roger
 
Re: Electrical box location

roger

you are kidding right, maybe you should read it again
 
Re: Electrical box location

If you must put them in the same stud cavity, you need to use the "putty pad" on each box to comply with the "This minimum seperation distance between metallic boxes may be reduced when "Wall Opening Protective Materials" (CLIV) are installed according to the requirements of their Classification."
 
Re: Electrical box location

MPD, no I'm not kidding, you read it again, and with out quoting the article tell me in your own words what it says and how it can be enforced, or better yet, what there is to enforce.

With no specific criteria or direction, it is no more than a piece of advice.

In this particular case, the FPN is more credible than the article it is attached to.

Roger

[ November 30, 2005, 09:04 PM: Message edited by: roger ]
 
Re: Electrical box location

roger

you must maintain the rating of whatever you are penetrating, so as an electrician or inspector you better know where rated assemblies are in a building, and how those penetrations are going to maintain that rating,
 
Re: Electrical box location

mpd, unless there is an AIA design and wall assembly in place, there is no rated assembly for an inspector or electrician to worry about, and even if this is known, 300.21 is still a waste of ink.

Building codes and UL assemblies already cover the requirements with out the pathetic little 300.21 hanging on their coat tails.

You should look at the UL orange books for further information.

Roger
 
Re: Electrical box location

you must maintain the rating of whatever you are penetrating, so as an electrician or inspector you better know where rated assemblies are in a building, and how those penetrations are going to maintain that rating,
Click to expand...
Exactly!
 
Re: Electrical box location

roger

I think 300.21 will make you look at the UL orange book, and who would worry about that penetration? and I thought the question was about a rated wall
 
Re: Electrical box location

Originally posted by mpd:
roger

I think 300.21 will make you look at the UL orange book, and who would worry about that penetration? and I thought the question was about a rated wall
Click to expand...
Now I will admitt you lost me, you have a designed rated wall and you as an inspector do not worry about a break in the membrane that is in fact a (or the) major part of design.

The penetration must be an assembly that is compatible with the wall or barrier. just applying a certain spacing, slapping on some fire caulk, five siding or a putty pad on a box doesn't mean anything if it is not done correctly.

Roger

[ November 30, 2005, 09:50 PM: Message edited by: roger ]
 
Re: Electrical box location

roger

you said there is no rated assembly an electrician or inspector has to worry about, then who worries about it?
 
Re: Electrical box location

MPD
I think you and Roger may have a minor communication gap.

I think (and Roger will let us know) Roger is trying to say is:

The wall and the boxes will have the rating. The boxes by themselves with whatever you may try to use to comply with the fire rating will not have a rating - it is the whole assembly including the boxes. UL has a list of somewhere aroung 100-110 ratings. Some construction will not resemble these ratings, then one will need to get an Engineering judgement. Most manufacturers of Fire Stopping will help provide these if their product can be used.


BTW: I have code books back to 1962. 300.21 is in the '62 NEC. The wording is still the same, and this wording came out long before firestopping was an industry. So that is why the wording either needs some massaging or should refer to other more current codes.

Current firestopping really became what it is because of the MGM fire, sometime in the late '70s or early '80s.

[ November 30, 2005, 11:36 PM: Message edited by: pierre ]
 
Re: Electrical box location

MDP, I had a punctuation error in my last post, this sentence
you have a designed rated wall and you as an inspector do not worry about a break in the membrane that is in fact a (or the) major part of design?
Click to expand...
should have ended with a question mark as I have done here.

I think we are pretty much in agreement, but I don't think 300.21 is worth the space it takes up.

As Pierre points out, with the other codes and standards of today in place it should be reduced to the last sentence, and "approved methods" is the key to the sentence.

Roger
 
Re: Electrical box location

The walls between rooms are 1hr firerated and they are using plastic boxes that are rated for 2hrs. The big questions is can you put 2 of these boxes in the same stud cavity. One serves one room and the other serves the adjoining room. Can you have them in the same cavity?
 
Re: Electrical box location

curtisd

my best advice would be to check the box listing
for that use, and check the plans to see if the wall in question has any details for penetrations
in the same stud space,

and roger, I see what you were saying, no wonder we could not agree, there was a slight communication gap,
 
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