Type II Home: Is NM Cable Applicable?

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GZ P.E.

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Hello all,

I am rehabbing a historical home that has steel framing, steel lathe walls filled with concrete and a typical wooden roof.

Because it is a total gutt-job, I will re-wire the entire house. Per the 2008 NEC's code book Article 334.10, I can utilize Type NM cable (1) in a single family dwelling. Additionally, the commentary states, "If a building is to be of noncombustible construction (i.e. Type I or II) by the Owner's choice, eventhough the building code would permit combustible construction, the building is allowed to be wired with nonmetallic-sheathed cable..."

Must the cable still be placed in a metal raceway if it is a single family dwelling that is classified as Type II construction?

Thanks!
 
the exception to 334.12 A 1 does not apply because 334.12 A 1 indicates that 334.10 1 allows the installation of nm cable.

out of curiousity, what kind of house is this that is historical but has steel framing ?
 
I would be careful, the NEC is not always the determining factor. In NYS, NM Cable is not permitted in Type I or Type II construction.

Check your local laws.

I wonder, who is going to install NM cable in a raceway as the wiring method in a Type I or II construction? Maybe for a short run, but not the entire building...
 
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type ii home

type ii home

the intention of the code is that if it is allowed to have a building from a combustible material than type nm is allowed. if techinaccly you could replace those steel components with combustible materials than technically this house can be wired with nm.
just because you have steel in it should not disqualify it from type nm use.
question is is it really type II or are you saying it because you saw steel in it.
 
GZ P.E. said:
Hello all,

I am rehabbing a historical home that has steel framing, steel lathe walls filled with concrete and a typical wooden roof.
Click to expand...
NM is a bad idea in the situation described - without extra care into protection of cable one could be setting it up for disaster or hassle at the very least.... While NM is allowed in metal construction - in concrete - no...
GZ P.E. said:
Because it is a total gutt-job, I will re-wire the entire house. Per the 2008 NEC's code book Article 334.10, I can utilize Type NM cable (1) in a single family dwelling. Additionally, the commentary states, "If a building is to be of noncombustible construction (i.e. Type I or II) by the Owner's choice, even-though the building code would permit combustible construction, the building is allowed to be wired with nonmetallic-sheathed cable..."
Click to expand...
If you want a building of non-combustible construction (by choice) - why wire it in a combustible method??? You've gone so far as to remove wood from the construction method... Seems like an oxymoron... I believe there is an FPN or description of a flame-spread test in 800 or one of the annexes???? Get a piece of NM and some MC and try it out for yourself....

GZ P.E. said:
Must the cable still be placed in a metal raceway if it is a single family dwelling that is classified as Type II construction?

Thanks!
Click to expand...
Why not use MC or AC as one would in this type of construction? Labor wise it is not much different than NM... Or if you were to take a few extra & costly steps of conduit - why not maximize it's use, save a lot of money and use THHN?
 
e57 said:
NM is a bad idea in the situation described - without extra care into protection of cable one could be setting it up for disaster or hassle at the very least.... While NM is allowed in metal construction - in concrete - no...
Click to expand...

Metal studs with wood or metal trusses, concrete filled walls w/furring strips and/or sleaves and NM-B is a common form of construction. At least in Folrida.
 
e57,

When pricing NM, it is more expensive than MC per 100' but I figured the labor associated with handling MC would eliminate my potential savings.

The house was originally built in 1935 with steel beams and concrete lathe stucco. Other than a couple of bad modifications in the 1970's, the home is still in its original condition. My objective at this time is to rehab the 2,600 sq/ft home. Because of the depth of this project, I am identifying all potential cost savings and with safety in mind, making informed decisions. Type II or III construction is not a top priority. But, if the cost associated with NM and MC are similar, it may be in my best interest to keep the home as a Type II structure.
 
nakulak,

This is eccentric to the neighborhood and the time period indeed. It was built in 1935. I think I will go to the downtown library this weekend to determine who owned the home. I would guestimate that it was someone that was weatlhy and knew exactly what it was that they were doing. I bet he wanted it to stand for 100yrs (and it looks like it might). It seems like everything around the house has withered away other than the structure itself.

If you interested in knowing more about the community, take a look at these links:

http://houston.bizjournals.com/houston/stories/2008/08/18/story3.html

http://en.wikipedia.org/wiki/Riverside_Terrace,_Houston

Thanks for your help!
 
GZ P.E. said:
ivsenroute,

For what reason would you not utilize NM cable in this instance?
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Better protection, closer to the original installation material for a historic house. The NM cable will be subject to more damage during pulls through steel and masonry. My opinion of course. Look at the NEC and see the difference between NM and MC as far as use is concerned and you may get a better idea.

You problably wont be using plastic boxes anyway due to the steel studs so the MC-AP will save you tons of time in labor anyway.
 
GZ P.E. said:
I am rehabbing a historical home that has steel framing, steel lathe walls filled with concrete and a typical wooden roof.
Click to expand...

This is most likely, not type II construction. Under the IBC it would not be, because of the wooden roof.
 
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