Recess Outlet in Block wall

Rze · 11-03-2007, 11:40 AM

A friend of mine has asked if it is possible to recess an outlet in a block wall. My experience has been that outlets are surface mounted. Is there a method to recess?

Dave

SwiftyMcV · 11-03-2007, 12:38 PM

Unless the specified electrical box was installed before completion of the wall and fed with BX, he's out of luck (meaning does he really want to spend the time hammer drilling out for a box that can slide in (some Arlington product Ive seen http://www.aifittings.com )

His best bet is to install a FS box and feed it with the appropiate conductor (Teck Cable if your in Canada and its outdoors) or if he can going through cider block use BX and enter it into the back of the FS box.

Stubbie · 11-03-2007, 01:08 PM

The answer is yes with some effort as mentioned by Swifty. What exactly is his situation where he wants to recess in block? Is he wanting to put this on the inside or exterior of the block wall?

J. V. · 11-03-2007, 01:15 PM

Rze,
I live in a cinder block house. I installed several receptacles in these block walls. It must be the type of block that has a cavity. Each block has two cavities. They are installed so that the cavity runs vertically from the bottom to the top of the wall. This enables you to find the cavity and install the receptacle. If it is a solid concrete wall this method will not work.
If you can see the blocks it will be very easy. Here is how I do it.

1) Find the section of block that is open. The middle of the block is solid.
2) Trace the box you are going to install.
3) With a ballpeen hammer bust a hole in the center.
4) Lightly hammer out the rest of the block until the box fits into the hole. You may need a chisel. Keep testing the fit as you chip away.
5) Once box fits nicely, run NM (Romex) through the open section of the block (the chase). A fish tape works well for this.
You will have to bust another hole for the cable, at the end where you are getting power. Like behind another box. You can only go up or down in the block chase. You cannot go horizontally.
6) After the wires are run, attach the cables to the box with NM connectors. Strip at least 8" of cable. Tighten the romex connectors on the unstripped part of the cable. Do this while the box is not in the wall yet.
7) Now chip the block to allow for the connectors.
8) Pack bottom of hole with newspaper. Plenty of newspaper.
9) Mix up some ready mix morter and pile it up in the hole. Fill it up good.
10) Push wired box into hole filled with morter.
11) Make sure it is flush. You will have to find a way to hold the box flush and in place until the morter is set. 24 hours.
12) Install devise and trim out (install the plate and covers)

Rze · 11-03-2007, 11:58 PM

Thanks guys. It is inside. It is the lower level of a quasi split level home. The downstairs is for his daughter when she returns from college to visit. Upper part of the wall is sheetrock, lowewr is cinderblock. He doesn't want the outlets high on the wall. Sounds like any solution is not going to be easy

Thanks

jwhite · 11-04-2007, 09:03 AM

I have recessed many boxes in block walls, and I can say for sure it is not easy.

One thing to watch for is that often times a cavity is poured solid in a block wall. As mentioned above each block has two to three cavities. When the blocks are stacked these cavities line up, one on top of the next. Inside those cavities is where the block layers dump all there scrap concrete. Often times, in addition, one out of evey so many cavities is intentionally poured solid to add strength to the wall.

So before you go hammering out a hole. Tap on the blocks with the back of a hammer and be sure you find a good run of hollows from rec hight up to the top of the wall.

A good trick for fishing the wire is to tie a six inch length of jack chain onto a light weight string. drop the chain from the top use the string to jeep bouncing the chain past junk concrete till the chain falls below the level of your outlet opening. then you can reach in and grab the string with a hook make of scrap wire.

HouseHelper · 11-04-2007, 09:45 AM

Use Wiremold. The procedures outlined above will work, but if, as jwhite says, the cavities are filled, you are SOL. The wiremold will be more expensive, but much, much easier.

J. V. · 11-04-2007, 10:25 AM

jwhite,
If the cavity is filled he will not get to punch a hole. He will know right away if it is open or filled. I sometimes drill a small hole to be certain.

I totaly agree about the mudders dumping mortor into the cavities. I like your trick with the string.
We did house remodel once and it had block walls. We cut about 10 feet of fish tape and chucked one end into a drill. Then pushed and jiggled until it passed. If we could not get it through we used the drill. It works real good. That fish tape spinning and flopping around in that cavity would clean out a path.
This is not the most easy job. But can be accomplished in most instances.