Inset an outlet into concrete floor

[SwingKing]

I'm considering trying to add an outlet in the middle of my family room and looking for some help. Right now I have a table and chairs in the middle of the room with an extension cord running across the floor. I'm replacing the carpet with laminate flooring next weekend and thinking about putting in a dedicated outlet.

The problem is the subfloor is a concrete slab. The only way I can see to do this is to cut a channel from the nearest side wall and then chopping a hole in the concrete for an outlet box. Anyone done anything like this before? Could I cause any issues with the slab by cutting a hole deep enough to add an outlet box? Any suggestions on cutting a 6 foot channel just big enough to a romex power cable?

Thanks!

-- Ken

[LJR]

Ken, you are correct, the only way to do that is cut a channel from the nearest wall and then create a hole in the concrete slab for the receptacle.

No, you won't create any strength issues with the slab by doing this. If you cut the hole for the receptacle all the way through the slab you may find out about some moisture issues under the slab which you will now see at the new opening.

Use plastic conduit and plastic boxes for the job. Don't bury romex directly in concrete.

Be aware of, and plan for, how are you going to make the transition from the trench you've sawed into the floor up intp the existing wall. Are you going to try to tunnel under that wall and have the wiring concealed in thw wall? Or are you going to surface mount something there for the transistion from the floor to the wall?

Good luck and happy sawing.

[TheRic]

I would bary a PVC pipe, you can always pull new wires if needed. You will have to pour some kind of concrete back on top to make sure the gap is smooth / flush with the rest of the floor.

When you cut the channel do NOT dry cut it. Use a method that uses water to keep the dust down. Concrete dust is very fine, and it gets everywhere. If you use a shop vac to clean up concrete dust, make sure it has a special filter that can handle concrete dust. If not you will be blowing it out into your basement, and probally the whole house.

I made the mistake three years ago, I'm still finding concrete dust. And it's a total B**** to get something clean that has concrete dust on it.

[SwingKing]

Thanks for the comments. I wasn't sure I needed to run the romex through a conduit, but it does make sense. I'm planning on using a diamond blade in my circular saw to cut the channel, but I hadn't considered the dust issue. I'll definitely figure out a way to use water to keep the dust down.

Thanks guys, I was sure there would be someone here that could help me figure this out.

-- Ken

[TheRic]

If you use a diamond blade, then you are suppose to use water (atleast mine told me too). I found what works best is: pump spayer, water bottle sprayer, garden hose (turned real low) in order from best to worst.

If you have a pump spayer, have someone spray the water on the blade (you are trying to keep the blade cool, bonus the water helps keep the dust down) use that and have someone else clean the sludge (wet concrete) up, or stop every so often and clean it up. If you can have someone with a shop vac trying to suck up any dust as soon as it leaves the blade / saw / cut line.

When it's wet you can scrape most of it with a putty knife into a dust pan. You can use a shop vac it probally would not blow out the exhaust (still would get a good filter just in case). I went the extra mile on keeping the dust down after my first fiasco with concrete dust all over. Try to clean up as much as possible while it's still wet. Less dust will get in the air.

If you cut two lines down the path, you should be able to knock out the middle. Might want to score across the path, every so often so it chips out, verses 1 long hunk that would be hard to get out.