NAIL PLATES !

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MD12297

MD12297

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Joppa, MD
So several of us are having a discussion about nail plates on metal studs for MC cabling. 330 says go back to 300.4 but 300.4 says holes bored in wood studs. In Maryland where I am from the inspectors interpret that to mean any framing member wood or metal. Another electrician from New Jersey says they don't require nail plates EVER on metal studs there. Anyone have a definitive answer or is this up to the AHJ?

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MD12297 said:
So several of us are having a discussion about nail plates on metal studs for MC cabling. 330 says go back to 300.4 but 300.4 says holes bored in wood studs. In Maryland where I am from the inspectors interpret that to mean any framing member wood or metal. Another electrician from New Jersey says they don't require nail plates EVER on metal studs there. Anyone have a definitive answer or is this up to the AHJ?

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Since 330.17 says to protect according to 300.4(A), (C), (D) then that's what you do.

If the holes in the metal studs are less than 1-1/4" from the edge then use plates or bushings

If installed parallel to the studs and cable is run less than 1-1/4" from the edge then use plates or bushings

Pretty straight forward!
 
Little Bill said:
Since 330.17 says to protect according to 300.4(A), (C), (D) then that's what you do.

If the holes in the metal studs are less than 1-1/4" from the edge then use plates or bushings

If installed parallel to the studs and cable is run less than 1-1/4" from the edge then use plates or bushings

Pretty straight forward!
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:thumbsup:
 
I fully agree with Little Bills post.

That said, in 30+ years running MC cable I don't think I have used a nail plate.

I have never notched a metal stud to lay the cable in it and I make sure I am not closer than 1.25" from an edge.

If there are multiple cables we just use a stacker type fastener to keep them away from the edges.

cable-stacker-dimensions.jpg
 
Plates are not required for running MC cable through holes in metal studs even when the MC cable is less than 1.25" from the edge which would happen if the metal studs were of the 2 1/2" or 1 5/8" variety.
 
This usually is not an issue with standard depth studs only with 2 & 1/2" deep studs that don't provide the required 1 & 1/4" set back. 300.4 A specifically says when run through wooden studs. Metal studs are never mentioned and that's where the real argument lies....

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iwire said:
But 330 tells us to follow it, in my mind there is no argument to be made.
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But why make it more confusing with the word "wood" in the title of (A)? Why does 330.17 not include 300.4(B)? Seems about as pointless to me as having the word "wood" in the title of (A).

I would say that most inspectors are going to be looking for the 1-1/4 set back or a protective plate, but in a somewhat rare situation the wording just isn't quite there to fully support that is what is required. My guess is the intention is to protect it though.
 
kwired said:
But why make it more confusing with the word "wood" in the title of (A)? Why does 330.17 not include 300.4(B)? Seems about as pointless to me as having the word "wood" in the title of (A)..
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It seems obvious to me, but I certainly could be wrong that 300.4 was written before 330.17 was added.

If you see a problem with the current wording maybe make a 'public input'.
 
iwire said:
It seems obvious to me, but I certainly could be wrong that 300.4 was written before 330.17 was added.

If you see a problem with the current wording maybe make a 'public input'.
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I see a problem, but not going to waste my time on it either.

It also doesn't effect how I intend to make my installs - they will still be 1-1/4 from the face of the framing member.
 
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