Concrete walls

[PNWSparky]

New to the forum and am looking for advice on installing boxes in concrete forms before concrete is poured? Boxes will be for outlets in a garage

 

[infinity]

There are a few ways to do it, the easiest is to makeup the box, mud ring and a length of conduit with a hook that will stub out of the form and can be picked up later. You would use one of these for each outlet location. Another method is to stub out just one and connect them all together within the form (mindful of conductor fill and derating if it applies). Make sure you tape up all of the holes in the box.

 

[Coppersmith]

Make sure you tape up all of the holes in the box!!!!!!!!!!!!

emphasis added

And tape the front of the box too. Use good duct tape. If concrete fills a box you will wish you never became an electrician.

 

[tkb]

I stuff the boxes with newspaper before taping them up.

 

[infinity]

I stuff the boxes with newspaper before taping them up.

That definitely helps too, even if some of the concrete seeps in it will be easy to remove.

 

[gadfly56]

I stuff the boxes with newspaper before taping them up.

Use a form release agent and fill with low-expansion foam?

 

[infinity]

Use a form release agent and fill with low-expansion foam?

For the most part if all of the holes are sealed and the box is fastened tightly to the forum hardly any concrete will enter the box. Electricians have been stuffing mud boxes with newspaper for over 100 years.

 

[augie47]

There are a few ways to do it, the easiest is to makeup the box, mud ring and a length of conduit with a hook that will stub out of the form and can be picked up later. You would use one of these for each outlet location. Another method is to stub out just one and connect them all together within the form (mindful of conductor fill and derating if it applies). Make sure you tape up all of the holes in the box.

Fortunately in decades of experience this is one task I have never confronted. Reluctantly I admit I don't follow the procedure you prescribed (underlined above). Just for my "learnin'"
would you elaborate a bit

 

[JFletcher]

Fortunately in decades of experience this is one task I have never confronted. Reluctantly I admit I don't follow the procedure you prescribed (underlined above). Just for my "learnin'"
would you elaborate a bit

Makeup =- preassemble. Does that help?

~~~~~~~~~~~~~~~~~~~~~~~~~

Oh, and dont tick off the masons. I had one tell me, not knowing I was an electrician, that he screwed over the mouthy site sparky by undoing the duct tape on the conduit stubs, put a trowel full of concrete down the conduit, and taped it back up.

Better yet, get the concrete supervisor/foreman a bottle of his favorite stuff*...especially if he knows more about setting boxes in block/concrete than you do.. It's amazing how far $20 will go in favorland. Instead of overlooking your mistakes, he might help you out. Making mistakes in concrete is costly.

emphasis added

And tape the front of the box too. Use good duct tape. If concrete fills a box you will wish you never became an electrician.

and if you miss one altogether you get to beg and plead to run surface mount conduit and boxes. :lol:

 

[MTW]

Concrete Boxes

Concrete Boxes

I have no experience in roughing concrete walls, but I would suggest having a look at Garvin Industries. They have a line of boxes made for this purpose. Also have blank and airtight boxes, for those special occasions.
https://www.garvinindustries.com/electrical-junction-boxes/concrete-slab-boxes/square-concrete-boxes

MTW