Outlet Box Projection?

[Greatwhitewing]

Outdoor receptacles under a deck roof. 1/2" plywood under 1/2" PVC beadboard to be installed later after electrical work.

How far out from the plywood, or flush, should my box be mounted? Should the box front be flush with beadboard? Slightly recessed? or fluch with the plywood?

I have removed plywood where I am installing boxes and using "new construction" blue plastic boxes.

I am putting metal hinged outlet covers over the outlets.

 

[RickP]

I don't think those metal hinged covers meet code anymore. When our house was built in 2005, we had to use "in-use" clear plastic covers over all the exterior outlets -- even the ones under a deck roof. Ours are like this one:
http://www.homedepot.com/p/Bell-1-Gang-While-in-Use-Receptacle-Cover-Enclosure-MM410C-8/100173013#.UdHxGTuTgcd

 

[Greatwhitewing]

What about the box mounting. I need to do that very soon.

BTW the circuit is already ground fault protected.

 

[pattenp]

Outlet boxes are to be mounted so that they are recessed no more than 1/4 of an inch from the finished surface.

 

[Charles (in GA)]

You don't want the edges of the box protruding much beyond the finished surface, the cover then won't seal to the surface, and if this is a damp or wet area you want the weatherproof face plate to keep moisture, bugs, etc out of the box and the wall. Most weatherproof box covers had a foam seal on the back of them, which needs to do its job and seal to the adjacent surface.

NEC 314.20 says that in combustible materials, the box must be flush or protruding from the finished surface, while in non-combustible surfaces such as tile or concrete, the box may be recessed as much as ¼" from the finished surface.

314.20 In Wall or Ceiling. In walls or ceilings with a
surface of concrete, tile, gypsum, plaster, or other noncombustible
material, boxes employing a flush-type cover or
faceplate shall be installed so that the front edge of the box,
plaster ring, extension ring, or listed extender will not be
set back of the finished surface more than 6 mm (1⁄4 in.).
In walls and ceilings constructed of wood or other combustible
surface material, boxes, plaster rings, extension
rings, or listed extenders shall be flush with the finished
surface or project therefrom.

Charles

 

[marty_p]

Thanks for the great advice, Charles!

 

[Greatwhitewing]

Is PVC considered combustible?

BTW my local well equipped hardware store doesn't even stock the cover plates that let the cord be plugged in and still cover. They sell the metal hinged/sealed cover plates. Doesn't seem to be code?

You don't want the edges of the box protruding much beyond the finished surface, the cover then won't seal to the surface, and if this is a damp or wet area you want the weatherproof face plate to keep moisture, bugs, etc out of the box and the wall. Most weatherproof box covers had a foam seal on the back of them, which needs to do its job and seal to the adjacent surface.

NEC 314.20 says that in combustible materials, the box must be flush or protruding from the finished surface, while in non-combustible surfaces such as tile or concrete, the box may be recessed as much as ¼" from the finished surface.



Charles

 

[pattenp]

PVC conduit and conduit bodies are not considered flammable. You need to look at the date sheet for your bead board.

Is PVC considered combustible?

BTW my local well equipped hardware store doesn't even stock the cover plates that let the cord be plugged in and still cover. They sell the metal hinged/sealed cover plates. Doesn't seem to be code?

 

[Greatwhitewing]

I haven't bought it yet. I am buying from a local lumber yard that is pretty high end. Not a homo depot or how lowes can you go box store..

PVC conduit and conduit bodies are not considered flammable. You need to look at the date sheet for your bead board.

 

[RickP]

Is PVC considered combustible?

BTW my local well equipped hardware store doesn't even stock the cover plates that let the cord be plugged in and still cover. They sell the metal hinged/sealed cover plates. Doesn't seem to be code?

I'm not a code guru, but I think it's a pretty recent change to the NEC. It depends on your local building codes whether or not the "in use" covers are required. If I were you, I'd just use the hinged metal covers, unless the outlets aren't covered by enough of the roof to protect them from a driving rain. My old house had metal covers, and the GFCI outlets would always trip in a driving rain even with nothing plugged into them.

Here's a link to a PDF that describes the differences: Gaylor.com

It says this on page 2: "A new code change for 2008 requires that all 15- and 20-ampere, 125- and 250-volt nonlocking receptacles shall be listed weather-resistant type receptacles and not standard devices."

 

[Greatwhitewing]

Thanks Rick. I was thinking of using both types. Hinged metal covers for occasional use outlets and the plastic shield for outlets that will have something plugged in all the time..

 

[Charles (in GA)]

Weather resistant is referring to the receptacle itself, NOT the cover. The receptacles are made with more corrosion resistant metals in them. Not your typical house or shop receptacles.

Charles

 

[Greatwhitewing]

The receptacles are weather resistant type that also have built in covers over the two voltage terminals. Box protrudes 1/4 to 3/8 from plywood.

Circumstances have changed and might be a little while before PVC is put up.