Firewall Outlet Box Placement(s)

Discussion in 'Electrical Forum discussion & Blog' started by KULTULZ, Jul 14, 2011.

  1. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    I am doing a condo kitchen remodel and replacing an existing firewall (5/8" fire rated drywall on wooden studs). Code says that the outlet boxes must have no more than a 1/8" air gap between the box and drywall cutout and this air gap is to be fire caulked.

    Now, does the box have to extend into the cutout or can a metal expansion ring suffice (the box installed at the rear of the drywall as to enable a more concise cut-out), the problem being cutting such an exact opening and hoping to have it hit the installed box?
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,239
    Location:
    Land of Cheese
    The box should be flush with the face of the drywall. If it is not, you need to use a box extender.
  3. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    THANX!

    So the box should be set to the outer surface of the drywall and an extension ring used if wall finishing material(s) is used.

    Makes perfect sense...
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    Where are you getting this information?
    I have never heard of any such rule
  5. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    First, I am not a licensed professional and gain what little knowledge I have from boards such as this and technical publications. Any guidance I receive is greatly appreciated.

    I understand that any opening in a firewall structure must be protected from fire blow-though, pipes, cables and outlet boxes. I have also read through many manufacturers materials that a box penetration be tight and caulked (either with caulk or a pad) to prevent any blow-through which makes sense to me.

    From- http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073984818&sequence=1

    While the above excerpt does not specifically call for caulking, it may be in another section I have not discovered yet.

    So to answer your question, more word of mouth than actual knowledge. Any help is appreciated. This is a condo one hour rated wall and the builder did a terrible job (IMO) (Example- Non-rated ice supply box in fire wall and plastic outlet boxes with no backing).
  6. DonL

    DonL Jack of all trades

    Messages:
    3,815
    Location:
    Houston, TX

    You are going the correct direction KULTULZ.


    Good Luck on your project.


    DonL
  7. DonL

    DonL Jack of all trades

    Messages:
    3,815
    Location:
    Houston, TX

    That is the way it is done here, in condos.

    I guess you did not get that memo.


    Enjoy your weekend.


    DonL
  8. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    THANX DON... appreciated...
  9. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    If there is two boxes with one looking into two different units that are in the same stud bay then protection is required.

    If there is only one box in the stud bay looking into either unit then nothing is required.

    A fire wall would separate the two units between the walls and again nothing would be required for the box.
  10. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    :eek:

    That explains the plastic boxes used by the builder and the fire caulking on the partition wall headers. The firewall is two separate studded walls between the units and now I see what you are telling me.

    So as long as there are two walls, one doesn't need to worry about blow out? The fire is considered contained within the unit (sprinklers also)

    You think you have it figured out and it bites you in the butt. I am assuming overhead can lights still have to be within a fire rated enclosure here?

    So in the grand theme of things, the builder was correct (I was assuming the inspector missed it) in not making the unit wall blow proof?

    THANX AGAIN gentlemen for the education.... :cool:
  11. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    Just a note, some plastic boxes carry a 2 hour fire rating.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,822
    Location:
    New England
    A double, or offset stud wall is often just done for sound proofing, and may only have minimal fire rating effect. That comes from blocking and the surface (like the 5/8" rated drywall). The comment about boxes facing either direction was about them being in the same stud bay. If there's only one in that stud bay, no problem. If there's one facing into each unit in the SAME stud bay, then you need to treat it differently since you then could have a cross-over point into both units; otherwise, the wall surface (drywall) would be the fire block.
  13. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    GOOD POINT... But who would guess? UL labeled, correct?
  14. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    I cannot see the adjoining condo receptacles.

    I only have six penetrations to worry about. I think I will caulk and use-

    [​IMG]

    -and cover guards (covers are plastic) just to be safe.

    Again, THANX GUYS! Proper info is difficult to find and understand... :cool:
  15. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    A fire wall will have rock between the two studed walls.

    If there is no rock between the studded walls then where is the fire protection?

    In a single family dwelling the wall that is between the attached garage and the interior of a house is a fire wall. A box that looks inside the home and a box that looks to the garage would require a fire pad.
    Although this is overlooked in most cases for a single family dwelling everyone worries about an apartment, why?
  16. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    MY main concern is liability. I surely do not want to be responsible for loss of life due to ignorance on my part. This is a kitchen re-do that just got out of hand due to poor builder craftsmanship. You wouldn't believe the electrical and plumbing faults I found behind that drywall. The whole thing snow balled on me.

    This is a dual wall with fire rated firewall (5/8") on either side with some additional panels added (previous crossover?) in between. There is a 3" air gap between the wall assemblies which I assume is for sound deadening. Fire rated QuietRock is going back up. It has sprinklers also.

    I was just confused about the whole thing until you educated me and for that I thank you immensely. It all makes perfect sense now but I just want to take a few extra steps. I now understand the differences in firewall design... :)

    I have just bought a house that has an attached garage and understand the firewall there. I will take it even further to not allow any fumes to enter the main house by sealing the garage off (no air leaks permitted).

    I will take a photo later today and show you how it was assembled.

    BTW- I am extremely anal if you haven't noticed.
  17. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    One of the things that I address on just about a daily basis is the compliance of an electrical installation. This comes up concerning Home Inspectors more often than not but every once in a while it comes up concerning an electrical contractor that has just entered the profession.

    Should an installation have been compliant when it was installed then it is compliant today even if we think it is unsafe. One example that keeps sticking its head out is GFCI protection. A house that has an outside receptacle that was built in the 60s is compliant with a regular duplex installed instead of a GFCI protected one. Would most think this needed to be changed to a GFCI device? Yes, but not required unless it was to be replaced due to any reason except the current code requirement.

    The same is true with the other trades. A washing machine with a 1 ¼ inch drain that was installed 20 years ago is code compliant today although a horizontal run would require a larger pipe to meet todays standards.

    What happens is someone new to the trades and not knowing the old codes would start making statements that this installation is not to code when they are in fact code compliant. I run into this in renovations all the time.
    Bottom line is; if it was compliant when installed it is still compliant today even if we think it is unsafe.
  18. KULTULZ

    KULTULZ Jack of all trades, Master of none

    Messages:
    85
    Location:
    ROCKVILLE, MD
    You misunderstood as I did not fully explain due to resizing photos (still learning here also). I realize what it is you are saying, but this is the first thing I found after stripping the cabinets-

    There was an illegal junction point @ the 20A MW outlet. I finally figured the electrician didn't pull enough wire and had to add to the run. The range outlet was also on this dedicated circuit.

    The more drywall I pulled, the more surprises I came across.

    I am concerned the neighboring wall was not properly built as a firewall which explains (hopefully) my wanting to make my side tighter.

    Comments welcome.

    Attached Files:

Similar Threads: Firewall Outlet
Forum Title Date
Electrical Forum discussion & Blog How can I add an outlet to a bathroom with no outlets? Jul 16, 2014
Electrical Forum discussion & Blog Ideal for Kitchen Retrofits. Adding outlets and data to a kitchen countertop. Jun 15, 2014
Electrical Forum discussion & Blog How to wire outdoor electrical outlet using old hot tub connection? Jun 3, 2014
Electrical Forum discussion & Blog Using grounding bar inside 3-gang metal outlet box Mar 14, 2014
Electrical Forum discussion & Blog Wet Bar Outlets Jan 13, 2014

Share This Page