MC cable in exterior wall

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Mr. Bill

Mr. Bill

Senior Member
Location
Michigan
Just curious how many NEC violations people see with installing MC cable in this manner. I'm telling the EC to rip it all out for NEC violations and because our own specifications tell them to install rigid steel conduit for exterior, above ground, concealed installations. The black coating on the block is the vapor barrier.

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I'm quoting these sections.

NEC 330.10(A)(11):

NEC 330.12(4): I'm not sure if cinder fill applies but there is mortar that dripped on the MC cable as the upper portion of the wall was constructed.

NEC 330.24: Bending Radius

Others? Or do people disagree with any of these?
 
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I am not sure that 330,10(A)(11) or 330.12(2) apply since we have no way of knowing if that MC is resistant to corrosive material or whether it meets the criteria of (A)(11).

If the requirements were for rigid pipe then I don't see why you even have to quote any NEC articles.
 
The MC cable appears to be typical off the shelf kinda stuff. But I do not know for sure.

I'm quoting NEC as an exercise in searching the NEC and then posting here to see if I've missed something or if there's another way to look at the situation.
 
I'm quoting these sections.

NEC 330.10(A)(11):
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Does not apply. Look at the definition in Article 100 of Location, Wet.

NEC 330.12(4): I'm not sure if cinder fill applies but there is mortar that dripped on the MC cable as the upper portion of the wall was constructed.
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Does not apply, this is certainly not cinder fill.

NEC 330.24: Bending Radius
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Even at the corner I don't really see a problem.

Others? Or do people disagree with any of these?
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So I guess that I disagree with all of your code citations. However that point is moot since the spec requires something other than what was used.
 
No way.

No way.

That SURELY, SURELY MUST be temporary. No way that is permanent. If it is, get rid of the EC and replace the bid. No way that is permanent. That has to be temporary project power.
 
76nemo said:
That SURELY, SURELY MUST be temporary. No way that is permanent. If it is, get rid of the EC and replace the bid. No way that is permanent. That has to be temporary project power.
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I have no idea if your joking or not. :-?

That MC will be covered by block, I don't see any NEC issue or anything inherently wrong about it.

If it does not meet specs well then that is a problem.
 
infinity said:
Does not apply. Look at the definition in Article 100 of Location, Wet.



Does not apply, this is certainly not cinder fill.



Even at the corner I don't really see a problem.



So I guess that I disagree with all of your code citations. However that point is moot since the spec requires something other than what was used.
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I agree with you on those points as well. Specs on that job are the only thing that could justify having to remove it. IMO.
 
iwire said:
I have no idea if your joking or not. :-?

That MC will be covered by block, I don't see any NEC issue or anything inherently wrong about it.

If it does not meet specs well then that is a problem.
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Wow, I guess that is the same opinion as tie wrapping pipe in trusses:grin: I wasn't joking. I have never seen a length of MC in a horizontal run span that far:rolleyes: No, all jokes aside, I would of guessed that as temporary:cool:
 
Judging from how straight it is I would guess that the supports are much closer than the code required maximum of 6' apart. Although to some this may be a little unorthodox it looks like the installer took the time to do a neat job.
 
infinity said:
Judging from how straight it is I would guess that the supports are much closer than the code required maximum of 6' apart. Although to some this may be a little unorthodox it looks like the installer took the time to do a neat job.
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it looks to me like they zip tied the M.C. on top of the brickeys steel straps that hang out of the wall, and then jiffy clipped it to the block once it went around the corner.
 
ultramegabob said:
it looks to me like they zip tied the M.C. on top of the brickeys steel straps that hang out of the wall, and then jiffy clipped it to the block once it went around the corner.
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I think your right, I had assumed it was clipped all the way until you metioned zip ties. :smile:
 
infinity said:
What part of that list would prohibit this installation?
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Nothing in that list would prohibit it. Just pointing out that the coated MC can be used where exposed to cinder fills. The standard Southwire MC does not list cinder fill.
 
330.10 (A) (10) I would consider it a damp location. Most masonry walls I've seen laid the cavity between the block and brick is almost full of mortar.


I personally would consider it a wet location at times. But I know the code does not agree. I have seen water run out of the weep holes at the bottom of brick walls after a long rain.
 
SmithBuilt said:
Nothing in that list would prohibit it. Just pointing out that the coated MC can be used where exposed to cinder fills. The standard Southwire MC does not list cinder fill.
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Mortar is not cinder fill. Seems that this is where the confusion may be.
 
infinity said:
Mortar is not cinder fill. Seems that this is where the confusion may be.
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I had always assumed it was. But after a search I have learned something new.






What about 330 (A) (10)?
In dry locations and embedded in plaster finish on brick or other masonry except damp or wet locations.
 
76nemo said:
That SURELY, SURELY MUST be temporary. No way that is permanent. If it is, get rid of the EC and replace the bid. No way that is permanent. That has to be temporary project power.
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This was the permanent wiring by the EC for all of the exterior lights over each exit door. When I talked to him yesterday afternoon he assured me that the cable was listed for use in this application. He said the field guy considered this a fixture whip which the spec permits as MC. I told him fixture whips are 6' in length, not 50'.

I wasn't sure if cinder fill was the same as mortar. Sounds like it's not.

The bend radius is still an issue. At the corner where shown and where it exits from the wall.

I didn't see any zip ties but it does look like he used the blocks' steel straps as a temporary support and then attached the clip supports.

He also disagreed with my first two Code citations. He asked if PVC conduit would be okay instead. I told him per plans and specs. So it sounds like he's going to run the circuit on the inside of the building now in EMT and punch thru the wall at each fixture location.
 
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