Concrete Floor Box

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mkgrady

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Massachusetts
Customer wants 2 floor receptacles in a new slab. Wood flooring will go on top of the slab. All the floor boxes I have located (T&B & Wiremold) are out of stock in my area. My customer, who was an electricain 20 years ago, thinks I can run a PVC conduit to a mud box. I've used mud boxes in block walls but I don't think they can be poured into a floor. Using a concrete rated 4" octagonal box seems like it would meet code but is that adaptable to a floor receptacle and flush plate? I can't picture what the parts wood look like. He is expecting a receptacle recessed inside a brass plate that is flush with the floor.
 
I would used an approved floor box. If you can't wait for one then run the conduit in the slab to the location and install a few layers of 12" X 12" Styrofoam or a small square plywood form at the box location. Order your boxes and install them later. Set the box and simply patch the 12" x 12" area with concrete.
 
That sound like a good plan, but I'd like to be able to tell the customer his idea will either not meet code or the parts won't give him the result he wants. I just don't know if either is true.
 
I forgot to say what Pierre summed up, that the floor outlet box needs to be listed for the application. If you can't get the box in before the pour provisions can be made to install it after the pour.
 
Trevor
It is funny sometimes how easy it is to solve some issues. I would in all my years of experience not thought of your resolve to this. I like how you would do this until the proper box comes in.
Another good reason to follow this forum.
 
Pierre C Belarge said:
Trevor
It is funny sometimes how easy it is to solve some issues. I would in all my years of experience not thought of your resolve to this. I like how you would do this until the proper box comes in.
Another good reason to follow this forum.
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This method grew out the need to install a bunch of floor boxes at the intersection of four 12" floor tiles. (This is what the architect wanted) So I ran the conduit to the general location and installed 18" X 18" plywood boxes at the location. After the pour was complete the tile guy snapped lines to represent the seams in his tile. I then used his lines to set the boxes at the intersection of the four tiles. The nice thing about setting the boxes after the pour is that the concrete height has already been established so leveling the boxes at the proper height is a lot easier than trying to set them with a transit or laser before the pour.
 
Pierre C Belarge said:
Tell him to look at
314.27 Outlet Boxes
(C) Floor Boxes.
Boxes listed specifically for this application shall be used for receptacles located in the floor.
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That's just what I needed. Thanks
 
So if I box out the floor box location and connect the conduit later won't this technically require another inspection before I fill the hole with concrete? I'm told the inspector is very fussy.
 
It may, but there shouldn't be an extra charge---Check with your inspector. I say, if you get to know your inspector, he/ or she "may not" be all that bad!
 
How come you didn't use the round floor boxes. Those allow for cutting off the excess above fininshed floor to be cut off with a rotozip or saw for final leveling. And they are listed floor boxes.
 
mkgrady said:
So if I box out the floor box location and connect the conduit later won't this technically require another inspection before I fill the hole with concrete? I'm told the inspector is very fussy.
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I would think that the fussy inspector would appreciate, rather than resent, the additional inspection request.
 
macmikeman said:
How come you didn't use the round floor boxes. Those allow for cutting off the excess above fininshed floor to be cut off with a rotozip or saw for final leveling. And they are listed floor boxes.
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That's what I ordered. I won't see them until Tuesday. I have never used them. They seem like a good product. I plan to have them stick up through the concrete higher than the finished (wood) floor and cut off what I don't need once I know the finish elevation. They come with some sort of ring that glues on after the cut is made. The ring is used to receive the recep and the brass plate. I assume the only problem I could have is setting the box too low, so I'll keep them pretty high in the pour. There doesn't seem to be a way to extend them. I wish I knew how to show a link to the product. Heck, I don't even know how to add a smiley face!
 
mkgrady said:
Customer wants 2 floor receptacles in a new slab. Wood flooring will go on top of the slab. All the floor boxes I have located (T&B & Wiremold) are out of stock in my area. My customer, who was an electricain 20 years ago, thinks I can run a PVC conduit to a mud box. I've used mud boxes in block walls but I don't think they can be poured into a floor. Using a concrete rated 4" octagonal box seems like it would meet code but is that adaptable to a floor receptacle and flush plate? I can't picture what the parts wood look like. He is expecting a receptacle recessed inside a brass plate that is flush with the floor.
Click to expand...

Sounds like your in for a fun job with him as retired electrician.Glad its not me.You just know he will be questioning every thing you do.Tell him if he is going to help then the price goes up $50 an hour.
 
MK, sounds like you ordered Carlon maybe?. They are alright but next time look at Hubbel's product. The glue business is ok but Hubbel's have a great screw locking mechanism for securing the trim rings. Imho it is far superior a method of support than the competition. As for cutting off the excess, I put in lots of these guys, so I made a sheet metal jig with a cutout for the box that I slip over the box before I use my pvc saw to cut it flush to finish floor. It helps to keep the saw from marring the floor around the box. Tell the flooring guys to cut right up to the box, the trim rings do not leave much of a margin for overlap.
 
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macmikeman said:
MK, sounds like you ordered Carlon maybe?. They are alright but next time look at Hubbel's product. The glue business is ok but Hubbel's have a great screw locking mechanism for securing the trim rings. Imho it is far superior a method of support than the competition. As for cutting off the excess, I put in lots of these guys, so I made a sheet metal jig with a cutout for the box that I slip over the box before I use my pvc saw to cut it flush to finish floor. It helps to keep the saw from marring the floor around the box. Tell the flooring guys to cut right up to the box, the trim rings do not leave much of a margin for overlap.
Click to expand...

I bought Lew Electrics PVC Floor Box. I never heard of them. Found them on-line. I found a box by Carlon in their paper catalog but it was rectangular. The customer wants round. I'll have to look for one by Hubbell just to see the difference.
 
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