romex

[keith gigabyte]

Bidding a multi family dwelling. It is a 3 story large home with basement partially below grade. It is being converted into 4 units..one on each floor level. It is a brick home build around 1910. with the exception of a few existing 2x12 floor joists the interior is new construction 2x4's and engineered wood beams. The exterior walls are original brick load bearing. Now that you have an idea of construction type, I feel it falls under type III construction in annex E.
I read and re-read 334 uses permitted and uses NOT permitted. As I read it I can use nm cable throughout correct?
Just always heard romex I is not allowed f building over 3 floors; and do we count basement since its finished? Which would make this building 4 floors.
I am going to check with the inspector but I don't like to ask a simple question like this and seem inexperienced.
Thanks.

 

[GoldDigger]

It used to be over three stories. Now it is any building required to be of Type 1 or Type 2 construction, leaving the specifics to other codes.

Note that many of us argue strongly that it does not mean any building actually built according to type 1 or 2, only buildings that were required to be built that way!

FWIW, when the limit was three stories, a basement was counted IF the basement was partially above ground, as in a home on a hillside.

 

[George Stolz]

The easiest way to make the determination is to look at the Code Data page in the first few pages of the prints, that is the determining factor for whether you can use in NM cable or not. Typically Types I, II and V Construction are explicitly called out there.

Edit to add: the latest trend is to have Type I on first floor, a three-hour PT slab between first and second, and then Type V for floors 2-5. Makes life interesting getting SER to meter stacks at grade.

 

[MyCleveland]

It used to be over three stories. Now it is any building required to be of Type 1 or Type 2 construction, leaving the specifics to other codes.

Note that many of us argue strongly that it does not mean any building actually built according to type 1 or 2, only buildings that were required to be built that way!

FWIW, when the limit was three stories, a basement was counted IF the basement was partially above ground, as in a home on a hillside.

Have thought for years that the type 1 and 2 restriction should not apply. I tracked down a CMP member on the issue.
Please read through 334.10(3) carefully. "Other structures permitted to be of Types III, IV, and V construction.
My take away was, IF your building could have been constructed to Types III, IV, or V....THEN type NM cable IS allowed. Panel member stated this is why (3) was developed to handle buildings remodels....say old factories or schools converted to apartments or where a developer wants to build structure to a higher standard but would still be allowed to use NM for wiring.

 

[George Stolz]

That's a cart vs horse. If the Code Data sheet calls out Type V construction and you build to Type I standards, there's no code requirement to wire it that way. The inverse is not true. I've seen wood studs installed in Type I Construction by mistake, and the GC had to jump through hoops to compensate but the MC we pulled was good to go.