romex in a comerical building

[mmartin20]

romex in a comerical building the local inspector says if I use romex in a conceal wall i would have to use 5/8 drywall. where does this come from?

 

[Gregg Harris]

romex in a comerical building the local inspector says if I use romex in a conceal wall i would have to use 5/8 drywall. where does this come from?

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:

1. One- and two-family dwellings and their attached or detached garages, and their storage buildings.
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. 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].
4. 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.
5. Types I and II construction where installed within raceways permitted to be installed in Types I and II construction.

 

[Dennis Alwon]

Be aware that NM cannot be used in a dropped ceiling of a commercial building.

 

[kwired]

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:

1. One- and two-family dwellings and their attached or detached garages, and their storage buildings.
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. 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].
4. 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.
5. Types I and II construction where installed within raceways permitted to be installed in Types I and II construction.

That in itself does not mention thickness of drywall, which is kind of what OP is asking (I think).

I don't think 5/8 drywall is necessary, any finish with at least 15 minute rating is acceptable.

 

[cowboyjwc]

That in itself does not mention thickness of drywall, which is kind of what OP is asking (I think).

I don't think 5/8 drywall is necessary, any finish with at least 15 minute rating is acceptable.

That is probably correct. Most people get overly concerned about 1 hour conditions when most commercial buildings are one hour (to a point) just by default. 5/+ 2 by 4 + 5/8 will give you one hour in most cases. 5/8 + 2 by 4 + nothing used to give you your rated garage wall, which was a modified fire wall 1/2 to 1 hour, but even that's no longer required.

Inspector probably just figures that since it's in a commercial building that it will be covered with 5/8 any way and also letting them know that it can't be run exposed.

 

[liquidtite]

Be aware that NM cannot be used in a dropped ceiling of a commercial building.

ive been on jobs were we ran nm in drop ceilings in commercial offices and it passed this is in nj.I thought you cannnot use nm if the prehung ceiling is being used as a plenum or the building is over a sertain amount of floors?