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Posted By: Admin Boxes in Block Walls - 05/25/08 04:01 AM
Quote
Attached are pictures of receptacles in boxes that are set too deep in block walls.

Section 314.20

Alan Nadon


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Posted By: GA76JW Re: Boxes in Block Walls - 05/25/08 04:49 PM
Unfortunatley i've seen that many times. It's really hard to keep an eye on the block masons when they decide to pour their blocks.
Posted By: Rewired Re: Boxes in Block Walls - 05/27/08 10:43 PM
Ya thats common I have seen that a lot of times as well!
Looks like the receptacle in the second pic down has taken a bit of abuse also..

A.D
Posted By: EV607797 Re: Boxes in Block Walls - 05/27/08 11:44 PM
Yep, most look better than half of the crap that we encounter around here. At first, I thought that pic #1 actually looked pretty good. The latest trick around here is to use bond barrels as screw spacers although those THHN "springs" look pretty creative as well. If we could get masons who speak English, we might not have these setback issues. That's another subject.......
Posted By: Texas_Ranger Re: Boxes in Block Walls - 05/28/08 08:08 AM
Some creative solutions... but looks very familiar. Here the electricians never know how thick the plaster coat is going to be, so they set their boxes in brick walls at a random depth and it's hit or misss if the plasterers have them meet the finished surface. Seen some that were recessed as far as 1/2". Of course mud rings are something you just don't use here... *sarcasm*
Posted By: johno12345 Re: Boxes in Block Walls - 05/28/08 01:21 PM
British metal boxes aka backboxes can be set in the wall way below the plaster line, it doesnt really matter. it isnt uncommon to see them 1" below the plaster line, you just use longer screws! This is because our socket and lightswitch fronts are only in one piece so the screws clamp the accessory to the plaster.

I will try to find a picture of one installed somewhere.
Posted By: Texas_Ranger Re: Boxes in Block Walls - 05/28/08 02:23 PM
Works too, but it's certainly not good practice. If the pasterer manages to leave a funnel shaped hole things get even worse because the face plate won't cover the entire gap...
Posted By: johno12345 Re: Boxes in Block Walls - 05/28/08 09:02 PM
Not best practice, no but in my experience it is difficult to get a plasterer to avoid filling a box completely! There is quite a bit of overlap on the socket front so you can get away with a few sins. With care, you can chop a box in and not need to repair the existing plaster.

Not saying they are perfect but seem to be designed around plaster and block walls compared to the ones in the above pictures which seem to be more suited to plasterboard walls.
Posted By: HotLine1 Re: Boxes in Block Walls - 05/28/08 10:56 PM
I would have a issue with some of the gaps around some of the boxes. The THHN springs would not fly, but the 'nut' spacers may be OK. Wonder if the 'springs' compress upon insertion of a plug into the receptacle??

As an AHJ, When I'm on site, the 'rough' is usually stub-up conduit first, and it's extended as the block goes up. The next time I see this may be on final.I have a few random covers pulled. Depending what I see, they may all be required to be pulled, and corrections made.
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Posted By: Texas_Ranger Re: Boxes in Block Walls - 05/29/08 10:30 AM
Personally I stuff newspaper or anything else available on site (think empty plaster or cement bags) into the boxes to keep them from being plastered. There are proper anti-mortar covers too.

Things get real nice once you have boxes tiled over...
Posted By: renosteinke Re: Boxes in Block Walls - 05/29/08 02:17 PM
The work shown in the pictures is pretty typical. Indeed, I've seen many far worse.

The little wire wraps are, despite appearances, not like springs. They are simply there to give a firm connection to the box. At that task, they succeed, resulting in a good, tight grounding connection by the screw, and little stress on the cover plate. Folding plastic 'caterpillars' are made, and sold, by electrical suppliers for this very task.

Also sold are plastic forms that slip into the box, and are a listed means of filling the gap between the box and the device. That brick may not burn .... but usually the painter will pack the gap with caulk, or mud - and the plastic forms also keep the gunk out of the boxes.

A similar problem arises when tiles are laid after the boxes are set. Here you have another problem; cutting tile isn't exactly a precise craft. Nor has the tile setter much reference as to the size of the plaster ears, etc.

Sometimes you're left with lemons - and all you can do is hope to make lemonade from them.
Posted By: alan bergold Re: Boxes in Block Walls - 05/30/08 05:27 AM
This is not so bad considering the situation..the masons are never perfect and we cant always be watching over them...The worst pic i seen was the one with all the small washers used for spacing...i would love to see a perfectly flush box but im sure that is a rare find in this situation...
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