The type of structure will trigger when and where and how.
334.10 Uses Permitted. Type NM, Type NMC, and Type NMS cables shall be permitted to be used in the following:
- One- and two-family dwellings and their attached or detached garages, and their storage buildings.
- Multifamily dwellings permitted to be of Types III, IV, and V construction except as prohibited in 334.12.
- 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. Informational Note No. 1: Types of building construction and occupancy classifications are defined in NFPA 220-2009, Standard on Types of Building Construction, or the applicable building code, or both.
Informational Note No. 2: See Informative Annex E for determination of building types [NFPA 220, Table 3-1].
- Cable trays in structures permitted to be Types III, IV, or V where the cables are identified for the use. Informational Note: See 310.15(A)(3) for temperature limitation of conductors.
- Types I and II construction where installed within raceways permitted to be installed in Types I and II construction.