Outlet Box - Back to Back Mounting

Status
Not open for further replies.
J

Justice

Member
Location
E. Central Florida
I am new here, Hi.

I ask only after a few hours of searching with no success.

I have a General note on my drawings:
WHERE BOXES ARE MOUNTED ON OPPOSITE SIDES OF WALLS, A MINIMUM SEPARATION OF 24" SHALL BE MAINTAINED.

Does this note refer to the NEC, Florida Building Code or NFPA for installation in Fire rated walls?

Any listing for the above for Non-Fire rated walls where a clearence of 24" must be kept?

Thanks for any help.
 
Welcome to the forum.

The only reason I can think of for the separation in a "non-fire rated wall" would possibly be for sound. I do not know of an NEC requirement in non-rated construction that would require such separation.

Pete
 
I recently installed boxes back-to-back that were in the same stud cavity, much closer to each other than 24". The inspector didn't have a problem with it, so I assume it's OK as far as the NEC is concerned.
 
Justice said:
I have a General note on my drawings:
WHERE BOXES ARE MOUNTED ON OPPOSITE SIDES OF WALLS, A MINIMUM SEPARATION OF 24" SHALL BE MAINTAINED.
Click to expand...
Many times, this is simply not possible.
There is a solution:
ca08008.jpg


[Hilti
CP 617 Firestop Putty Pad]

Hilti has many products to suit the various penetrations that require firestopping.
 
allenwayne said:
Well we didn`t design the firewall or lay out the kitchens.We were NEC compliant,but the fire dept would tag the install due to the double penetrations.The electrical inspector passed the rough in but the fire inspector failed the wall inspection.
Click to expand...


I love their arguement "... GC argued that we should have bid for firecode."...personally, I don't care if it EVER passes fire code (that's my canned response to the GC).


allenwayne said:
.... the GC paid almost as much in extras as they did for the bid.Like a sprinkler flow tamper system that had no provisions for power. and wall colums that were 6 ins off from the floor plan and underslabbed risers.
Click to expand...
Are we on the same job ???
$:D$
 
I`ve encountered the 24 in rule in a multi family dwelling.No penetrations are to be within 24 in. to both dwellings within the same wall cavity.This was a 24 in. on centered wall studding.It came to bear when the kitchens were identical on 2 identical back to back units.So the receptacles couldn`t be moved.Answer was to have the GC pay to 5 side one box or supply putty pads.They opted to putty pad one box since it was less of an expense.
 
I believe "five side" means to wrap the box with the same material used to acheive the rating.

I often see notes that prohibit outlet boxes from being located in the same stud cavity to provide sound attenuation.
 
What 5 siding a box is really simple.Drywaller wraps the outlet box on all sides including the back with 5/8 fire rated drywall and muds it in.This eliminates them being considered being within the same cavity and penetrated on both sides of 2 units.When there is no room to move a receptacle like in the situation I described back to back identical kitchens there are 2 choices.1 - 5 side one or putty pad one.The cost that was entailed to the gc was around $25.00 a box to 5 side each box or use putty pads at 1/2 that cost.We bid the job per receptacle and the GC argued that we should have bid for firecode.
Well we didn`t design the firewall or lay out the kitchens.We were NEC compliant,but the fire dept would tag the install due to the double penetrations.The electrical inspector passed the rough in but the fire inspector failed the wall inspection.There was no choice they supplied the putty pads and we wraped the box.Now from the start I brought this issue up to the Gc and he said they were approved plans and not to worry.So much for logic and planning.It was a poorly planned project and when it was all said and done the GC paid almost as much in extras as they did for the bid.Like a sprinkler flow tamper system that had no provisions for power. and wall colums that were 6 ins off from the floor plan and underslabbed risers.
 
Status
Not open for further replies.
Top