block house wiring

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Old 06-13-02, 07:19 AM
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block house wiring

I am wiring an old block house. Even the inside walls are block. I was told I could run the wires between the sheetrock and the block between the furrowing boards. These boards are only 3/4 ". I was not told this is accepted by code, hard to belive it would be. This method does not seem safe to me as someone might someday drive a nail into the wires, not to mention that it may be easier for a fire to start if something happened with the wiring that close to the sheetrock. I am running my wires from the service panel down through the block on that wall, under the floor, into the block at locations directly under the receptacles and up to the receptacles. Lot of work but safer, I feel. And I really feel that a small piece of conduit is called for ant place I have to bust/cut the block.

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Old 06-13-02, 12:49 PM
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YOu are allowed to install your nonmetallic sheathed cables [aka Romex] wires in the void area that is only 3/4" deep found between your finished wall and your cement block.

You are allowed to install your nonmetallic sheathed cables [aka Romex] wires in the void area of cement blocks.

You are not allowed ot install your nonmetallic sheathed cables [aka Romex] where embedded in adobe or concrete or anyother type of masonry. The term embedded means to patch that hole you made in that cement block where the wire enters that void area of that cement block with mortor or cement mix would be a violation. To patch your holes in that cement block you need to use duct seal stuffed into the holes. This duct seal will stay pliant through the years and will not harm your cables.

To create a hole in a void area to place a receptacle box in it is best done by a small diameter circular cement saw. Use a small hammer drill drilling a hole in each corner of the marked out receptacle box outlined on the block by pencil. Then use the cement saw and cut a line on all four side of the marked out box on that cement block void area as deep as your can without too much overrun on your saw cuts. Then take what is called a star drill or even a heavy small headed hammer and crack that marked out area. The cement should pop into the void area making a decent shaped hole matching your receptacle box. I would use plastic device boxes and mortar them into place using cement patch mix after you have placed the wires into the box from inside the block's void area.

Often times an electrician will come from the bottom using a hammer in the crawl space. IF you use a 20 oz. cleated hammer and crack that same spot on the void area or use a star drill and crack that star drill a couple of time you can knock a round hole into the cement block void area leaving a round hole to pass your Romex through to the receptacle box area.

Hope these ideas makes you project endeavor a bit easire and neater.

Good Luck

Wg
 
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Old 06-13-02, 03:49 PM
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tx for the response. I may go for the between the wall board and block method since it is okay and a lot less going under the floor. I think I got a spider bite on my rear under the floor. Going to the doc tomorrow.

P.S. I did drill holes with a hammer-drill to outline my holes for the receptacle boxes then knockedthem out with a hammer. But, I also knocked the block out down to the floor, removed a strip of wall board and removed the baseboard and 3/4 furrow strip in the one room I had started. Lot of extra work if not necessary.

Interesting info on sealing the hole where the wire enters the block too.
 
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Old 06-14-02, 07:36 AM
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No protection needed for wire when it is in a 3/4 "space behind finished wall? I had thought maybe a metal plate would be called for where the wire goes throught the furrowing boards, but I can't see the point if it is going to be almost against the finished wall at any given point.
 
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Old 06-15-02, 08:57 AM
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YOu are allowed to install your nonmetallic sheathed cables [aka Romex] wires in the void area that is only 3/4" deep found between your finished wall and your cement block.

Then where possible, I can just run a line to the middle of room (in the attic) and branch off from a make-up box and run my wires down the walls from the top in the 3/4" space between the block and the wallboard? Lot less wire, wallboard replacing and work where possible. Sure hope no one hits a wire with a nail while hanging pictures.
 
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Old 06-15-02, 12:07 PM
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Where a cable passes through a board and the wire is within 1 1/4" of the wall surface you must us nail protection. When in a wall void no clearance is required.

If your cable is passing through a board that wire is contained in an area that it can not move if hit by a nail forcing the nail through the cable causing a short.

If a cable is in a wall void a nail won't hold too much just poked through the wall boarding. If that nail hits a cable in a wall void the cable will move out of the way as long as that cable is not pressed against the wall behind it or the nail doen't hit a tight wire that can not move when the nail hits that wire dead center.

The NEC is concerned about wires passing trhough a board contained in that hole through the board. The NEC is not concened about wires running in void areas of wall spaces.

Use nail protectors wherever a cable passes through a hole in the framing members. Otherwise you need not use nail protectors concerning wires running in a void wall space.

Hope this helps

Wg
 
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Old 06-15-02, 08:00 PM
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When in a wall void no clearance is required.

Unless, as stated in previous statement, right? Sorry to be so adamant about this, but I just couldn't see running wire in a 3/4" space where it could get hit by a nail and not be able to move with it. So I still need to get some kind of tracking to place the wire in if I come down the walls. And rip more wall board off.

That or come from bottom through the block as I started the first room.
 
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Old 06-15-02, 10:01 PM
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It is normal practice to fish wires down walls that were slatted out with a 3/4" void area. Just install nail protectors where you pass through the boards to get into the void area of that wall. Don't worry about the 3/4" deep wall space it is allowed to fish cables down that wall or fish up that wall.

Wg
 
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Old 06-16-02, 06:40 AM
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Don't worry about the 3/4" deep wall space it is allowed to fish cables down that wall or fish up that wall.

Let me get this real clear. I can fish the wire up or down the wall between the wallboard and the block, even though there is only 3/4" between the block and the wallboard. Not talking about in the void in the block but between the block and wallboard where the wire cannot give if hit by a short nail because of the block behind it. Does this not go against the 1 1/4" rule, or does that only apply when going through a board or furrowing strip? In my case that would only be at the top as the walls are furrowed vertically with one strip going horizonally at the top and the bottom.
 
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Old 06-16-02, 09:47 AM
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You are correct. YOu are concerned that the wiring can not shift in the 3/4" space but it can and will. A nail being driven into that void area would not have to be driven hard and would not hold much becuase there is nothing to nail other than the wall covering that won't hold much. When you put a nail trhough that wall covering the cable can shift side to side. If a cable is in a wood hole that cable can shift neither front to rear or side to side because of the round hole containing it in place.

YOu may fish wire in a 3/4" void of a wall between the cement block and the wall covering no problem it is done everyday in the industry.

Wg
 
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