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theatretch85 04-06-2009 11:54 PM

Half-height Cinder Block wall Electrical
In my new house (new to me) the previous owners at some point in the last 32 years "finished" off the basement but in the process cut several corners mostly in electrical. I plan on posting a new thread of the growing number of electrical nightmares I have since discovered. One of which being the outlets installed in this basement bedroom.

They used 6cu boxes for the outlets and switches while running 12/3 to each box. The switch box only had one cable to it, but 2 of the 3 outlet boxes have 2 runs each (in and out). I am replacing it all and had thought about using the 4" boxes with single gang mud ring in the 2x2 firred out space in front of the cinder block wall. The wall only goes up about 3-4 feet and stops below the windows; the current outlet in this wall has romex stapled to the side of the 2x2 and it runs up underneath a plank that covers the top of the cinder block wall to meet up with the stud wall the windows are in. This makes it real easy for a nail or anything to puncture the romex in this "shelf" or anywhere along the 2x2 strip.

I was thinking just running 1/2" conduit between the boxes and just notching the 2x2 firring strips to allow this, but then got to thinking about the corners and transitioning to romex once it gets to a "normal" 2x4 stud wall.

What is usually the preferred way to install outlets in this 2x2 space? If I use the 4" metal j-boxes with the 1/2" single gang mudring, can I notch the backside of the 2x2's to alow for running romex along the bring wall instead of having to run conduit or flex conduit? Since the 2x2's aren't really 2" and are more like 1 1/2", would this be a problem with clearance from the sheetrock wall?

Anyone have any suggestions or reccomendations?

Bob Mariani 04-07-2009 05:39 AM

Your ideas to use these boxes and conduit will help. Notches are fine, but you need to install notch plates over the holes. These are found in the electrical department and are metal plates that are nailed over the hole to protect the wire from errant nails.

theatretch85 04-07-2009 07:22 AM

I kinda though I might still need the nail plates, I was hoping not to have to do that with how many I am likely to need. Are nail plates still required if I use 1/2" conduit?

Here is a picture of the switch and box for this particular room:

Notice the Red wire is clipped off along with the ground wire, and the black wire has at least an inch of wire insulation stripped off. And there is barely enough wire to work with in this box, never mind the code required 6 inches.

Here's a close up:

Bob Mariani 04-07-2009 08:20 AM

This must not be inspected so it must be an illegal basement. Meaning a new owner will assign no valued to it. Seems like you are doing so much work, get a permit, do it right.

No nail plates are not required for conduit. See NEC article 300.4 A (1) which says raceways or cables in concealed locations through bored holes must be 1 1/4" from the edge will reguire steel protection plates. but: Exception #1 excludes EMT.

theatretch85 04-07-2009 12:16 PM

I believe the entire basement was done with out any inspections (even the toilet was 4" too close to the wall in front of it). In my area, no permits are required to start electrical work, just rough inspections and final inspections (yes I called the electrical department and verified). I am completley re-wiring this bedroom and the downstairs bathroom and will be doing some wiring in the laundry/utility room as well.

Thanks for that section of code, so it looks like I could probably make a small notch at the back side of the 2x2 strip and still run romex instead of needing to run the conduit. Since I believe the strips are really 1 1/2" so if I only notch it 3/16" - 1/4" for the romex I should be ok then (or if there is enough space behind the strip to run the romex). I have at least 2 cinder block walls that total about 25-30 linear feet in this room and the other two walls are stud walls, so those won't be an issue.

InPhase277 04-07-2009 01:02 PM

You could use a 4" square box with a 1/2" or 5/8" mudring. This would give you the box volume you need to have multiple runs in and out. The Raco 196 boxes have a bracket on the side.

220/221 04-07-2009 02:14 PM

Shallow plastic 4s boxes w/mud rings

Nail plates at the furring.

Conduit would be wasted effort IMO.

theatretch85 04-08-2009 12:16 AM


Originally Posted by 220/221 (Post 256446)
Conduit would be wasted effort IMO.

Thanks, good to hear it from someone else.

How do I deal with the romex where it needs to be secured within 4" of the box and have to staple it to the side of the 2x2? It will be closer than 1 1/4" and on the side of the 2x2 strip so protecting that with a nail guard would be kinda hard.

I was thinking of using the 4" metal boxes with the 1/2" mud ring. I like the idea of using the 4" boxes in an area where I can use the extra space and where I might want to put in two outlets in the same box later on.

Finally got the last of the sheet rock out of this basement bedroom, below are pictures of 2 of the 3 outlets.

You can tell which outlets are different by looking at what color screw the wires are attached to. Notice how they didn't use the white wire at all, and then switched neutral/hot between the outlets....

The way I understand it, if I am abandoning electrical wire in the wall since it runs up into the Sheetrock further than I am replacing, I can simply cut it at both ends and write on the romex "Dead - Abandoned in place" and be ok right? I have 5 ends of the cable that I have cut and have done this way and will be running new wire (12/2) to the new outlets. I may end up ripping it out in the event I have to remove the sheetrock on the other side of the wall in the garage (its cinder block up to the garage floor, then its a standard stud wall).

InPhase277 04-08-2009 06:45 AM

Put a 1x4 near each box to staple the wires to. You only need to secure the wires within 12" of the box if the box has clamps, so that should give you some play as to where you secure the cable.

theatretch85 04-08-2009 07:31 AM

Ah, so is a cable considered "secured" if it runs through a 2x2 strip within 12" of the box (that is without a wire staple)? Since the box is 4" and the standard On-Center is 16" that would leave me with just under 12" between the box and the edge of the stud. And using the metal boxes I will have clamps on all the wires feeding into the 4" boxes. I'll just have to get a large handful of nail plates to protect the romex as it passes through the stud wall. Thanks for all the replies!

220/221 04-08-2009 07:02 PM

You don't need to staple 4" from the box.

6" if the box has no clamp. 12" if it has clamps.

4s plastic shallow boxes have clamps.

I would staple it to the block, in the grout, away from the 2x2's.

This is why I don't like metal boxes with NM cable. Plastic is non conductive and adds another layer of insulated protection.

theatretch85 04-08-2009 11:49 PM

I just bought a half dozen 4" plastic boxes and single gang mud rings today. Figure its also one less ground pigtail for a box being fed with romex. Though one thing I forgot to get were the nail plates, just another trip i'll need to make.

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