NM Concealed not any more!

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david

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Type NM, Type NMC, and Type NMS cables shall be permitted to be used in the following:
(1) One- and two-family dwellings.
(2) Multifamily dwellings permitted to be of Types III, IV, and V construction except as prohibited in 334.12.
(3) Other structures permitted to be of Types III, IV, and V construction except as prohibited in 334.12. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.

I was always taught this section excluded NM cable in types I and II construction. But rereading the wording in this section it is a permissive statement the language does not exclude Types I and II. Maybe the Sentence should read Type NM, Type NMC, and Type NMS cables shall (Only) be permitted to be used in the following: Any how the point is moot for me here in Pa., since the NEC became a referenced standard of ICC electrical code.

1202.2 Nonmetallic-sheathed cable. The use of Type NM,
NMC and NMS (nonmetallic sheathed) cable wiring methods
shall not be limited based on height, number of stories or construction
type of the building or structure. ICC Electrical/03

334.10(3) Types III, IV, and V construction----- Cables shall be concealed.
My first thought was NM in Other Structures should be concealed because 1202.2 only state that NM not be limited based on construction type this section in the ICC does not exclude limiting the use to only concealed areas. In other structures required to be III IV and V. Except there is no foundation to limit NM cable to concealed areas In types I and II construction.

I am left to conclude that 1202.2 gives permission to use NM cable Exposed or Concealed in All Building types (I,II, III, IV and V) I mean the use of NM cable is wide open except as prohibited in334.12
 
Re: NM Concealed not any more!

This is a controversial subject around here. Most home inspectors write up exposed romex as a hazard. Some say it is not allowed under a certain height, like 8 feet for example. I am pretty sure the IRC mentions no exposed romex under 8 feet or something like that.
It can be a real pain for the property owner when the garage and laundry is wired with exposed romex as it has been for fifty years now all of a sudden it's unsafe and they have to pay to have it remedied for the buyer.
 
Re: NM Concealed not any more!

Monkey
I?m not really addressing NM cable in R3,R2 (one, two, & multifamily dwellings ) I?m looking at the use in commercial class buildings. I?m saying that from what I am reading in the ICC electrical code, you can use NM cable in all classes of build restricted only by 334.12 NFPA 70/2002
 
Re: NM Concealed not any more!

An urban legend that`s all.I also have heard that 8 ft rule but have never seen it in writing.Subject to physical damage is a matter open to interpetation and that is a pretty vauge restriction as subject to physical damage can constitute many conditions that the NEC doesn`t clarify.
 
Re: NM Concealed not any more!

David, I would check your administrative rules. Most states do not adopt the Interniationl Electrical Code. I know our state doesn't.
 
Re: NM Concealed not any more!

By the way I?m talking about structures required to be Types I & II. Not less restrictive classes that are I & II by design choice
I really think the case can be made that since the NEC is taking the position that NM is only unrestricted in Types lll, lV and V and restricted to concealed spaces in other structures III, IV and V and does not allow it in types I and II. Since the ICC Electrical code simple allows NM in all types of structures then turns it over to the NEC to materials and wiring methods. NM should be restricted to concealed spaces in types I and II.
Does anyone else fill that this logic is correct?
 
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