ECN Forum Forums General Topics of the Trade General Discussion Area Setting boxes in a block wall

Masonry boxes with extensions is my way to get the KO's back into the cinder block cavities. Plenty of duct tape is used. I also install an extra long pigtail at the rough-in.

Recommend ENT/SMURF TUBE with conductors ALREADY installed whenever practical. Combinational raceways with PVC sch 40 below grade and ENT up into the cinder cavities is practical, too.

If you can't install the conductors, install pull lines.

Don't hesitate to bump up the raceway one size for longer runs. 3/4" is a minimum inside a building, 1" is the practical minimum for any pipe that leaves the building.

These are all pretty short and straight runs so stuffing the wire in will be easy. I am going with 3/4". I already installed the ground pigtail, I know better. You will never get a ground screw in there after the cell is poured
I am surprised they don't come that way.
We are talking about 5 columns with a couple boxes in each in a 350 sq/ft room.
I am going to home run them all onto a big Carlon box so my wife can change her mind about things. I know she will, I've seen her do it

I worked on a prison for about 13 months setting boxes with the masonry crew.

I had best luck using 4x4 boxes and deep (1" or 1-1/4") mudrings. You can tie the boxes forward with wire across a scrap of ENT.

Also, you can avoid the connectors at the boxes on poured walls. Leave the ENT long and chop it short after the pour is dry. That way your boxes are adjustable - and quickly installed - as the blocks are being laid.

It's been awhile and working with masons can range from terrible to easy. A case of beer given for after work can sometimes work wonders.
We always would pre make a bunch of 1900 boxes with about 5' of 3/4 pvc coming out of the top. Since they have to lift the block over the pipe, it shouldn't be too long and there should be plenty of couplings and glue on hand. Pigtail the ground and thread some doubled up tie wire through the back of the box holes and bring it out the front of the deep p-ring with plenty of extra.
Then we would duct tape the whole thing, poking the tie wire through the p-ring.
Communication was the key and if you let most of the masons I used to work with know where and when to put the boxes, they had no problem cutting it out and setting them in.
Then we'd take a cut piece of pvc and use the tie wire to snug the box up to flush (on finished block).
We keep a stash of pieces of busted up block to stick behind the box to snug it in, but a lot of time the masons would take care of that and throw some mud in there too.
Many times when they first hit the job they would need power to be hooked up for their saws, so that was a good time to get everything straightened out how it would happen, but I know what you mean about the dance thing.

OK I made some plywood fixtures to hold the boxes in and poured them with the dowelled cells. I think they came out great and the stucco man will hide all my sins. They sure are not going anywhere.
http://esteroriverheights.com/electrical/double_box.jpg
http://esteroriverheights.com/electrical/single_box.jpg

I've "chased masons" a lot in the past, and I've always done it the way wiking described.