Romex or mc

[Anonymous]

I was under the impression that you could not use Romex in schools, churches, commercial bldgs. etc. That you had to use conduit or MC. Can you clarify the NEC code on this?

[imported_Ron]

The code didn't address the NM Cable issue in that manner.
1999NEC limited to less than 3 stories with some other restrictions. 2002NEC limits based on fire resistance rating of the construction.

[Anonymous]

Ron, thanks for the reply. Do I understand that something like this scenario would be correct. "If the building is constructed of wooden studs in walls and wooden joists etc. The MC would be required, whereas if the building was all steel constructed with a concrete floor it would be ok to use the Romex."?
Thanks for your time. I really appreciate it.
Bob

[imported_suemarkp]

You kind of have it backwards in that NM cable is typically used in buildings that are easier to burn down -- perhaps there is a cause and effect here!

Here is what the code says for uses permitted for NM cable:
(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.

334.12 denies its use in some specific areas like hazardous areas, motion picture studios, storage battery room, elevators,... no mention of schools or churches though.

I don't know what types III, IV, and V construction are. The NEC Annex E describes the fire rating of these types, but doesn't explain much.

[Anonymous]

Very confusing for me. A company moved into a 1 story all steel constructed building with 6 offices built inside this building constructed of wood 2X4 walls with drywall, ceiling- armstrong 2X4 tiles. The offices were NM (Romex) wired the main building was conduit. Before they could open their doors the building had to be updated. Doors restrooms etc. We had to take out all the NM and run conduit with MC drops in the walls. Fine I could understand this.
We go to a church assembly hall, 1 story, newly remodeled, all wood construction with drywall, has a kitchen and seats 120 people. had been recently inspected before use. They wanted us to add some OH fans. I went there expecting this to have conduit and MC wiring. Wrong. It was done completely in Romex.
Can someone explain the logic of this to me? I really don't want to ask the inspector, I think you know where I am coming from.
Thank you for your time.
Bob

[Anonymous]

I was under the impression that you could not use Romex in schools, churches, commercial bldgs. etc. That you had to use conduit or MC. Can you clarify the NEC code on this?

Isn't the use of romex vs. conduit based on the use of the building and the number of floors the building? Meaning if the building is over 3 floors, it is required to be in conduit. Also if certain uses require conduit such as commercial garages with hazardous material, theaters, motion picture studios and more. Article 334 of the NEC spells it out.

[imported_Ron]

dan316,
You will find that the 2002 NEC has changed the rules. Use is based on many things including construction fire resistance ratings. The 3 story rule is not around anymore.

[Wgoodrich]

Chapters 5 is where you should be looking. Places of assembly is required to be on conduit or flex. There are some exceptions to this rule.

A commercial building is a class one structure. The state fire marshall's office will declare a fire rating of these commercial buildings. If these commercial buildings are non fire rated then nonmetallic sheathed cable may be used no matter how many stories high.

Check out places of assembly, types of use such as paint or other explosive products being used.

Examples

Grain elevators have beaswings of corn that is very flammable.
Factories that sand blast certain metals such as magnesium is also an explosive condition. Magnesium dust is explosive and in a class 2 hazard location.
Chemicals such as lacquer paint has expolsive fumes.


Most of these areas are found in Chapter 5 of hte NEC specific uses of buildings.

Just because it is commercial does not require conduit.

Fire rating and use declard by the Fire Marshall's office for fire rating sets you wiring style.

Churches are places of assemblies conduit is requried.
Places with stages are a key element of places of assemblies also.
Schools are a class E that also requires conduit.

Check out Chapter 5 for specific use buildings.

Hope this helps

Wg