Hi guys, what's the best way to install a single outlet box on an ICF wall. Any suggestions appreciated... Box type and installation method...

I used plastic boxes; found some that were just the right depth for the Fox Blocks 2-5/8" foam depth. I cut out the opening with a SawZall, then pop out the foam. I placed them next to a fastening strip so I could screw it down. I used the boxes with a mounting flange on one side. I also put a blob of construction foam behind it, and a contractor told me that that's all that's needed, but I like mechanical fastening, just in case. I took a cheap electric chainsaw and mounted a couple skate wheels on the bar to control the depth. I used that for horizontal wire runs. For vertical runs, I cut a corresponding access hole directly below in the basement, and dropped a red-hot 1/2" ball bearing in the upper hole. The hot ball burns down through the foam, and comes out in the access hole. I put tin foil in the lower hole to keep my ball from burrowing on down. Once the cable was threaded, I shot foam in the hole to secure the wire, and my inspector was fine with that, as there is no way to staple the cable.

https://www.youtube.com/watch?v=4pTvF4TZ1h4

its roug but you get the idea

Posted By jdebree on 16 May 2016 06:48 AM
I used plastic boxes; found some that were just the right depth for the Fox Blocks 2-5/8" foam depth. I cut out the opening with a SawZall, then pop out the foam. I placed them next to a fastening strip so I could screw it down. I used the boxes with a mounting flange on one side. I also put a blob of construction foam behind it, and a contractor told me that that's all that's needed, but I like mechanical fastening, just in case. I took a cheap electric chainsaw and mounted a couple skate wheels on the bar to control the depth. I used that for horizontal wire runs. For vertical runs, I cut a corresponding access hole directly below in the basement, and dropped a red-hot 1/2" ball bearing in the upper hole. The hot ball burns down through the foam, and comes out in the access hole. I put tin foil in the lower hole to keep my ball from burrowing on down. Once the cable was threaded, I shot foam in the hole to secure the wire, and my inspector was fine with that, as there is no way to staple the cable.

Excellent. Thanks. This is extremely helpful.

Posted By billnaegeli on 16 May 2016 09:03 AM
https://www.youtube.com/watch?v=4pTvF4TZ1h4

its roug but you get the idea

Thanks Bill!

CARLON blue boxes are what I'm using - screw the side tab to the ICF web, then after the wiring is in place, shoot some spray foam around it to further lock it in place.

CARLON Model # B118B-UPC (single gang box), http://www.lowes.com/pd_10004-223-B...27461&pl=1

CARLON Model # B232B-UPC (2 gang box), http://www.lowes.com/ProductDisplay...&cId=PDIO1

Posted By arkie6 on 16 May 2016 07:32 PM
CARLON blue boxes are what I'm using - screw the side tab to the ICF web, then after the wiring is in place, shoot some spray foam around it to further lock it in place. CARLON Model # B118B-UPC (single gang box), http://www.lowes.com/pd_10004-223-B118B-UPC_1z0xc7b__?productId=3127461&pl=1; CARLON Model # B232B-UPC (2 gang box), http://www.lowes.com/ProductDisplay?partNumber=10005-223-B232BR&langId=-1&storeId=10151&productId=3520414&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1

Thanks. That's helpful. Have any of you had issues with the Carlon boxes being loose after the wiring is complete and the sheetrock is up? I've read somewhere that the box wasn't as secure as a metal box that has been secured with a concrete nail through the back.

Due to this possibility- when teaching the install class - I always suggest tapcon of box to concrete. Regards

I'm going to suggest you check code before you use a metal fastener though the back of a plastic box. The issue is that a loose wire could light the screw up, and the screw could light up (electrify) else where in the house, by either leaking current though the concrete to the rebar, or direct connection to the rebar. Generally if you are going to fasten though a box you need to use a grounded metal box. That way the worst a loose wire could do is pop the breaker, rather than create an undetected shock hazard.

Posted By dave111 on 17 May 2016 10:41 PM
I'm going to suggest you check code before you use a metal fastener though the back of a plastic box. The issue is that a loose wire could light the screw up, and the screw could light up (electrify) else where in the house, by either leaking current though the concrete to the rebar, or direct connection to the rebar. Generally if you are going to fasten though a box you need to use a grounded metal box. That way the worst a loose wire could do is pop the breaker, rather than create an undetected shock hazard.

Hi Dave, I wasn't suggesting a metal screw/nail through a plastic box, but rather only through a metal box. I've heard however, that the side mounted plastic boxes screwed into your plastic strips in the ICF blocks can become loose and feel flimsy after use. But, since I've only read that once I wanted to hear others' opinions. Your point about the grounding is a great one. Thanks for the heads up!

They make plastic boxes with recesses in the back designed for screws- I saw some at Home Depot yesterday. You still need to check with your AHJ before proceeding; sometimes they're funny about this stuff.

One of the problems with mounting boxes directly to the concrete is finding one that is the correct depth so that the face of the box ends up flush or ~1/8" recessed from the face of the drywall. My ICF forms use 2-1/2" foam plus 1/2" drywall = 2-7/8" to 3" deep boxes. I couldn't find any locally that were that depth. 2-3/4" is the closest I could find and that was just a 1 gang box. 1 gang, 2 gang, and 3 gang boxes are all different depths, at least the ones I measured locally at Lowes and electrical supply houses.

I don't think there is anything to worry about the box moving if you screw the side tab to the ICF web with a couple screws and shoot some expanding spray foam around the box to tightly fill the gap between the box and the ICF foam. Plus, your switches and receptacles have tabs on each end that extend beyond the box and clamps the box to the drywall unless you cut out too much drywall around the box.

If you really want to attach the box to the concrete, one option when using plastic boxes, assuming they have a hole in the back (modifying the box invalidates the UL listing and may be an issue with an inspector), is push-in type plastic rivets like those often used on automobile plastic panels.

Something like this:

http://www.autoconsumables.com/ekmps/shops/227sparts/images/push-fit-plastic-rivet-8mm-hole-22mm-collar-black-537-p.jpg

http://i.ebayimg.com/images/g/Gp4AAOxyepRRwunO/s-l300.jpg

http://www.workshopsupplies.co.uk/contents/media/fix112.jpg

Has anyone used the Inexo boxes designed for ICF? They look to provide a unique solution with the "claws to hold it into the foam. I suspect once its foamed in it would be pretty stable. Also has side tabs if its next to a mounting point.

http://www.kraloyfittings.com/Content/Products/Product.aspx?ProductId=49

Nudura's video on electrical shows them for a moment.

https://youtu.be/5-UdF_2n16Y?t=1m41s Inexo's video https://youtu.be/6awEQ-0NeZI

Inexo's video

https://youtu.be/6awEQ-0NeZI

Inexo Boxes are great! Fast and easy to install. Solid hold. Only downside is cost (likely around triple the price of the steel box), but I would pay the extra money vs using a steel box and foam/tapcon, simply for the speed and ease of install.

I just topconed metal box to concrete

I used the plastic Carlon boxes.

The B118B-UPC as mentioned above works well for where you just have sheet rock going up. These.. For the kitchen or bathroom where you need to adjust the depth for a back splash for instance. Model B121-ADJ

[URL=http://s660.photobucket.com/user/craigtoo/media/Box_Capture.jpg.html][/URL]


You do need to fold the ears in. This allows it to stick out about 0.75in in the "most shallow" position. Not good for just Sheetrock, but great for sheetrock, plus backsplash / tile etc.

Both work very well and are secure.

It is extremely easy to cut the hole with a jigsaw set at about 2.25 inch depth of cut, pop out the foam push in the box, screw it to the webbing in the ICF. BAM. So easy a mechanical engineer can do it. So far, that's been my experience.