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Flush mount outdoor lighting
What is the best way to put in a metal box for flush mount outdoor lighting in precast concrete walls?
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Posted 2014-07-24T17:38:24+0000  by press press
 
You can recess a pancake box into the concrete, drill through the back of the recess and access the wiring inside your basement.  The caveat is that you can't go from pancake box to pancake box because of box fill limitations.  You'd need to install junction boxes inside the house so that only a single run of cable or pair of wires go into the pancake box.

I'd probably use a 4" or 4 1/8" diamond hole saw to make the initial cut and get a nice, neat circle.  Depending on how many fixtures you want to install I might think about renting one of the small rotary hammer drills that can accept a small chisel to help remove the material.  You also want to get the bottom of the hole reasonably flat and right angle grinder might come in handy.

Once you have made the recess, drill a hole large enough to accommodate the conduit and box fitting through the concrete wall with a masonry bit.  If you're using NM-B (aka Romex) then I'd suggest "sleeving" it with a short piece of PVC conduit as it passes through the concrete.  Obviously if you live in an area that requires metal conduit, use that.   I would also run a nice bead of silicone caulk on the back box, around the fitting to keep any water out.  Attach the box to the concrete with a couple of Tapcons or other anchor of your choice. 

Best Answer

Posted 2014-07-27T02:50:32+0000  by Adam444
Flush mount means that the fixture sits on the surface and the electrical box is recessed.  You can't do that unless you remove some of the concrete.  Is that what you want to do?
Posted 2014-07-25T12:35:10+0000  by Adam444
Hello press.  Welcome to the Community!

The best way would be to build the electrical conduit and boxes into the concrete forms before you pour the wall.

Once the wall is poured, then both a hole for the box and some way for wiring to get to it will have to be cut into the wall.
You can mortar these in once installed and use concrete screws as well to secure the boxes.
It is a lot more work than just surface mounting.

Chris.

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Posted 2014-07-25T19:00:14+0000  by Chris_HD_CHI
Yes to Adam444 question.  And thanks for the info Chris
Posted 2014-07-25T19:13:45+0000  by press
How are you planning on getting power to what you want to install this fixture.  Can you tap into a circuit inside the house or are you planning on coming down from the attic or up from the basement/crawl?
Posted 2014-07-26T00:34:49+0000  by Adam444
To Adam444   I plan on installing several outside light fixtures to the outside of my basement walls which are precast walls 9 foot high. The boxes need to be around 7 feet up. I already have power to these locations , wire is already ran from the inside to these locations. I guess I need to drill and chisel a hole so the box can fit inside the wall and secure it with wood and screwing the wood into the walls from the inside.
Posted 2014-07-26T14:27:19+0000  by press
Thank you Adam444 I really appreciate  your info. I think I can do it with no problems.
Posted 2014-07-27T03:49:45+0000  by press
 
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