Multi Use Buildings

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scnkapc

scnkapc

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Northern Kentucky
For a mixed use building (non-residential on first floor, residential on third and fourth floor) can you use NM Cable in the non-residential space?
We were told that because the building doesn't meet the types described in 334 we can not use NM Cable in the non-residential space but can use it for the residential units upstairs.
 
scnkapc said:
For a mixed use building (non-residential on first floor, residential on third and fourth floor) can you use NM Cable in the non-residential space?
We were told that because the building doesn't meet the types described in 334 we can not use NM Cable in the non-residential space but can use it for the residential units upstairs.
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I'd go with what you were told... assuming it was your AHJ that told you that. If it was another entity, ask the AHJ to be certain.
 
Old 1940's existing brick and mortar with wood studs and floor. They are constructing a 2 hour rated drywall ceiling to separate the 1st floor from the 2nd floor.
 
That 2- hour ceiling is for occupancy separation. It does not make it two buildings. You have one building. You have a 4 story building.
 
The way I understand Article 334 and Annex E in the 2011 Code is that NM Cable is mostly used for residential. I get that. Annex E talks about the types of construction: I, II, III, IV & IV.
Again as I understand it these types of construction are for multi-family structures.
The structure that is in question is an existing structure built in the 1940's with brick & mortar with wooden floors and wood studs. The 1st floor is being renovated into a non-residential space (retail shop).
The 2nd and 3rd floors are existing residential units. To have the proper fire rated between the 1st floor and 2nd floor they are constructing a 2 hour rated ceiling on the first floor.
Now here's the question:
If the structure is multi-use, non-residential and residential, can NM Cable be used to wire the entire structure?
OR,
Because it is a multi-use structure does the 1st floor have to be another suitable wiring method other than NM Cable?
 
scnkapc said:
Now here's the question:
If the structure is multi-use, non-residential and residential, can NM Cable be used to wire the entire structure?
OR,
Because it is a multi-use structure does the 1st floor have to be another suitable wiring method other than NM Cable?
Click to expand...

In my opinion the question may not be if you can use NM cable.
The question may be if you must conceal NM cable in the walls ceiling and in floors providing protection from physical damage and a fire barrier.

Here you would not be allowed he NM cable in accessible attics in unfinished basements and other exposed areas.
As already pointed out you are not in a multifamily dwelling, you are in other types permitted to be III, IV, and V
 
Informative Annex E in the NEC tells you (in nowhere near enough detail) what the types of building construction are, in terms of fire resistance. Type I through Type V.
Your building is definitely not Type I or Type IV, but it may based on your description be II (not likely) or either III or V.

From there, you look back at Article 344.10 and 344.12 to see where NM is allowed.

As noted by other posters, where a height limit in stories is mentioned in either E or 334, it refers to the total height of the building, not the height of that portion used for a particular occupancy.

You will be governed by 334.10(2) for the residential portion and maybe (check with AHJ) by 334.10(3) for the bottom floor only.

There will be requirements for the fire resistance of wall finish of any walls that contain NM in the non-residential portion, if it is allowed at all.
 
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