I’m about to pour a patio and while I’m at it, I figured this would be a good time to run some wires under it. Our house is L shaped and the patio will be set into the inside corner of it. I’m planning to run wires out to the opposite corner from the house, but that will be easy. What I want to know is if there is a type of outlet box that can be set in the concrete so I can have an outlet in the middle of the patio. My gut tells me know, it seems like if anything is plugged into it, it’s going to get flooded the first time it rains…that would be bad. The only thing I can come up with is setting a bigger box into the concrete (think spinkler control/valve box that you see in the grass near in ground sprinkers) and then having the outlet box being upright, but that would be to big, and I’m not that concerned with it. So…is there such a thing?
Use an outdoor electrical outlet. They are sealed to not allow moisture to get into the outlet or wires.
I’m looking for something that would be sitting flat on the concrete (on the ground). You see them all the time in malls at stores, but I’ve don’t recall seeing anything outside.
I’ll use that type of outlet at the far corner where I’m running the other wires two, but I was hoping for something in the center as well.
IMHO, putting a floor outlet in a outdoor location is just asking for trouble.
That’s kinda what I thought. I really couldn’t envision a good/elegant way to make it work.
There are special outlets that have a screw-on cover, designed for floor mounting, but I have never seen a waterproof one, and even if they existed, I wouldn’t trust it.
Sure, but these are above ground level.
In my experience, anything set at ground level is going to end up filled with water…
There are appropriate outlets. Go to your local electrical warehouse (NOT Home Despot) and explain to the counter guys what you want to do. They’ll hook you up.
Remember that any outdoor circuit will need to be on a GFCI.
I’ve been doing electrical for a little while now and have not seen anything that could be set into the ground in a wet location. Current code require outlets it wet locations have a protective bubble on them that not only protects the outlets themselves but also would protect the outlet while a device is plugged into it. like this one:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=238634-45875-MM410C&lpage=none
With your sprinkler box idea you could mount an outlet on a little post inside the box. but the practicality of using the outlet would be a pain. take the cover off the sprinkler box open the weatherproof cover plug the device in.
I think it would be much simpler to put an outlet on a post at the edge of the patio and use an extension cord to get to the middle when needed. If you think such a cord would be a hazard(ie you entertain allot on the patio and people trip on the cord) you could run a conduit big enough to snake an extension cord through from the center to the outlet on the edge of the patio. It could even double as a drain.(preferable not while your using the cord.) That way you could just unplug it at the outlet when you don’t need power.(not that I’d suggest using a extension cord as a permanent power source That would be against code.
The first article to reference for this project is 300, and Table 300.5 states that the minimum burial depth is 6" for residential branch circuits rated 120 volts or less with GFCI protection and maximum overcurrent protection of 20 amperes, for direct burial in a trench beneath 2" concrete, or beneath a 4" concrete exterior slab with no vehicular traffic, and the slab extending not less than 6" beyond the underground installation.
If you’re going to use a raceway originating within the dwelling, e.g. nonmetallic conduit, LNMC, or other listed raceway, 300.50(E) requires a seal with an identified compound so as to prevent the entrance of moisture or gases…
Next is 314.15 Damp, Wet or Hazardous (Classified) Locations.
(A) Damp or Wet Locations. In damp or wet locations, boxes, conduit bodies, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the box, conduit body, or fitting. Boxes, conduit bodies, and fittings installed in wet locations shall be listed for use in wet locations. FPN 314.27
314.27© Floor Boxes. Boxes listed specifically for this application shall be used for receptacles located in the floor.
All references 2005 NEC.
So long as the key word accumulating in 314.15(A) is met, and the rest of the installation meets code, and all equipment is listed and labeled for the application, I would see no reason to fail the installation. One thought would be to set up your pour with diagonally sloped forms, and do it in quads, such that each quad has 1/2" of fall (assuming 10 x 10-that’s a sneeze less than 1/8"/foot) from the center device box to the perimeter, thereby shedding water and helping to avoid the problem in the first place.