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Re-Wiring an old kitchen - question about furred-out walls

Re-Wiring an old kitchen - question about furred-out walls

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  #1  
Old 05-09-11, 12:52 PM
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Re-Wiring an old kitchen - question about furred-out walls

We are currently remodeling our kitchen, and have reached the point of electrical rough-in.

In order to maintain required clearance for an island, fridge, etc, the masonry walls have been furred out with 2x2's instead of re-framing with 2x4's. Yes, the cumulative 4 inches made a huge difference in layout.

Walls in question are 3 courses of brick, 2x2 PT furring strips, with soon-to-be 1/2" drywall on top.

Now, however, comes the question of how to wire this while maintaining code compliance.

I've got the wiring laid out such that I am able to utilize nothing but 1 1/2" deep metal boxes with 1/2" plaster rings and not go over on box fill (whew).

From what I understand, stapling NM cable directly to masonry is not a great idea, although by doing this, from what I can tell, would give the required 1 1/4" setback.

Would using AC (BX, what have you) alleviate the 1 1/4" setback issue?

Any thoughts, besides framing out with 2x4" and going that route (already had that argument with the wife, and I lost.)

Thanks for any help!!!
 
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Old 05-09-11, 01:01 PM
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Originally Posted by mikeygstl View Post
Would using AC (BX, what have you) alleviate the 1 1/4" setback issue?
Technically no, but I think it would be reasonable to pose this to the inspector to see if he will approve it.

Any thoughts, besides framing out with 2x4" and going that route (already had that argument with the wife, and I lost.)
You could use EMT conduit. The inspector also might allow NM if you use stand-offs from the 2x2 studding so the cables are "floating" in the stud space, thus less likely to get hit with a screw when aiming for the stud. You may be able to use UF-B cable instead of NM-B fastened directly to the brick, but I will need to check on that.
 
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Old 05-09-11, 01:28 PM
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Okay - am I reading something incorrectly, or do you think I could simply use plastic standoffs on the sides of the 2x2's to hold the cable in the cavity?

I guess I could bend EMT, but going around windows to get to the sink area is going to be a new 'art' for me to learn...
 
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Old 05-09-11, 01:45 PM
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Originally Posted by mikeygstl View Post
Okay - am I reading something incorrectly, or do you think I could simply use plastic standoffs on the sides of the 2x2's to hold the cable in the cavity?
Maybe, that is not universally accepted by inspectors but some of them do because the cable is 1.25" from the stud horizontally instead of depth.

I guess I could bend EMT, but going around windows to get to the sink area is going to be a new 'art' for me to learn...
It's not that hard to do and EMT is pretty cheap when you ruin the first couple pieces (everyone does). I believe they also sell prefab fittings at Home Depot, Lowe's, etc.
 
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Old 05-09-11, 01:55 PM
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Thanks ibpooks. I'll try emailing the problem and ideas to the inspector and see what he has to say.
 
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Old 05-09-11, 02:05 PM
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Okay - last post of questions on this subject (I think):

One length of romex per conduit, otherwise it could be considered bundling?

Terminating the EMT at the ceiling, using a bushing of course, would be fine - no need to run it into an (accessible) box to break out of the tubing?

And last, but not least, secure the EMT to the brick with straps every 4.5'?
 
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Old 05-09-11, 02:13 PM
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One length of romex per conduit, otherwise it could be considered bundling?
Best practice to not use NM-b in conduit. Instead use individual THHN wires. You can have up to nine #12 in half inch EMT. Since you only need one ground wire (if you choose to use a ground wire) that would be four circuits. probably all you need.
 
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Old 05-09-11, 02:35 PM
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Originally Posted by mikeygstl View Post
One length of romex per conduit, otherwise it could be considered bundling?
Correct.

Terminating the EMT at the ceiling, using a bushing of course, would be fine - no need to run it into an (accessible) box to break out of the tubing?
Correct, at least for the spot where NM comes into the conduit system. When going from box-to-box with a complete conduit in between I would use THHN conductors in black, white, green.

And last, but not least, secure the EMT to the brick with straps every 4.5'?
Within 36" of each box and every 10' thereafter. Half straps to the masonry with tapcon, expanding anchor, ramset, etc.
 
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Old 05-09-11, 05:33 PM
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You also use thhn in conduit because it is cheaper AND individual conductors carry more amps per nec than RX.
17c/ft for indivual conductors while ~$100 for 250' RX
 
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Old 05-09-11, 05:59 PM
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Wire

Check your math. 17 cents x 3 wires = 51 cents.
 
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Old 05-09-11, 06:54 PM
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Here is a good graphic from Mike Holt.

MikeHolt.com
 
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Old 05-12-11, 12:00 PM
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Hmm - following the graphic from Mike Holt, and after hearing from my inspector that this is a 'grey' area and that they pass work done as shown by Holt:

Is aluminum clad MC (aka MC-Lite) acceptable for contact with Masonry? I do not see an individual designation in the IRC or NEC about it, and can't find much info on Southwire's website either.

I don't feel comfortable running NM along brickwork - afraid over time the NM will abrade and fail.
 
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Old 05-12-11, 12:29 PM
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MC should is okay for surface mount on the masonry. I personally think that plan would be just fine and if the inspector is okay with it, then go for it. He is right that the code is not explicit in this situation, using vague terms like "subject to damage". The intent is to let the inspector decide on the individual case.
 
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Old 05-12-11, 06:42 PM
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In my area the AHJ has made it clear that aluminum armored MC cables are not suitable for use on masonry or concrete surfaces so in those applications MC Tuff (steel sheathed MC cable) is commonly used. The decision is based on

Type MC Cables Uses Not Permitted:
Where exposed to destructive corrosive
conditions unless the metallic sheath is
suitable for the conditions or is protected
by material suitable for the conditions (page 3)
http://www.acewireco.com/pdfs/AFCCATALOG.pdf

PVC jacketed MC cable would also work, but the price is somewhat higher.

That being said, I frequently see installations of aluminum MC cables on masonry and concrete that has passed inspection. When you have many inspectors, some points and issues can get overlooked and some inspectors nitpick the fine points more than others.
 
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Old 12-29-11, 06:46 PM
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Wel, kitchen is complete, and electrical passed first round, no questions asked.

Thanks for all the advice on the forums.

I spoke with the inspector here and found that the 1 1/4" IRC rule can be satisfied with the halex standoffs. Using these proved better than any other option. So, a few nail guards, a bunch of plastic standoffs, and about 300 ft of romex later, all is well.

Thanks again for all the advice.
 
  #16  
Old 12-30-11, 07:07 AM
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Thanks for the feedback. Enjoy your new kitchen.
 
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