electrical in concrete floor

[Bigrhamr]

I want to put some runs of conduit in my floor in a few locations so I can pull power to machines without tripping over wires or having them hanging from above. The best plan I can come up with is to use a 4x4x4 PVC J-box with a blank cover and set it 1/4" below the surface with a slightly larger piece of 1/4" plate covering it. The plate stays there until I want to tap into that box, then pull it off and put conduit into the cover and start pulling wires. (Yes I will remember to put pull rope in the conduit first)

Has anybody done this? Better ideas? Problems?

 

[Tscott]

I would think that a good electrical supply store would have a box specifically made to be placed in a floor. I believe the covers are usually made of brass and the box itself is made of either brass or stainless steel. I think you would be better off getting a purpose made product for this. It would **** to have to replace a cracked box in the future. Besides I think once you decide to add a receptacle into the box, it will be very hard to get everything flush if you don't get something designed for the job.

Tom

 

[kbs2244]

It will work.
But remember to use "sweeps," or double 45's, for any corners.
The wider radius curves make it a lot easier the pull though

 

[Bigrhamr]

Thanks Tom,
thats what I thought too about the purpose made boxes. First tried a basic electrical retailer who didn't seem to understand what I was talking about. Then a Platt and Eoff electrical supply house, both of whom are industrial suppliers. They both pointed me to the J-boxes, said use outdoor rated ones and they should be fine in concrete. To clarify I don't want to put a receptacle in the floor, I just want to be able to bring a conduit up out of the box. The 2 applications would be to put a receptacle on each fab table for grinders and hand tools and to hardwire machines like Ironworkers, brakes, rollers, saws, etc...

 

[Palmetto]

This is the box we put in the slab of my new home. I have 3 floor outlets in my living room. Should work for you too.

here is another shot, its the tall one in the back....

I am pretty sure these came from Lowe's.

 

[Palmetto]

(Yes I will remember to put pull rope in the conduit first)

if not, you should be able to use a fish tape.

 

[z28toz06]

you dont have to pull rope in them. Just take some string and tie one of those plastic shopping bags on the end and **** it through the conduit with a shop vac. Ive done 400 foot string pulls this way.

 

[OldCarGuy]

I installed plastic conduit under the floor from an outside wall that the load centers are located. That comes to the surface at the center of my workshop. Where I have a vertical post made of 3" square hollow tube. That I welded plate on the bottom and lagged to the floor. Then I mounted several 4 X 4 boxes on J channel that’s welded to the vertical tube. EMT conduit from the boxes to the PVC conduit. One box I have two 20 Amp duplexes. The other two are for 240 Volt Three Phase power for my machines.

This keeps the outlets off the floor. And water, dirt and grim from entering the electrical receptacles.

It’s a good idea to put the PVC conduit into the gravel base. Rather then into or at the bottom of the concrete. The conduit acts creates a stress point and the floor may crack at that point.

The electrical pole with the work boxes is just left of the Kennedy tool box. The bottle of Dykem Layout Blue is sitting on top of the receptacle box. And directing in front of the 3" square tubing...