type NM-B Wire in Factory

[shawn73]

Inside our automotive factory we are building a new office. It is built using wood studs and perhaps a drop ceiling. I was told that it is not legal to use type NM-B W/G wire in an industrial enviroment. Is this correct? If so, where can I find this code? I did read that it isn't legal in dropped/suspended ceilings,unless in a family dwelling. 334.12 (A)1 Thanks for your assistance.

 

[peter d]

Re: type NM-B Wire in Factory

It depends. You say "pehaps a drop ceiling." You are correct, NM is not permitted above drop ceilings unless you have local ammendments.

It's best to play it safe and install MC, or find out exactly what type of ceiling will go in.

 

[shawn73]

Re: type NM-B Wire in Factory

I guess it is to be a normal dry-walled ceiling. What if there were no wires in the ceiling but there was a drop ceiling? Describe MC.(???) Thanks

 

[peter d]

Re: type NM-B Wire in Factory

If this is an automotive factory, there are certainly plant electricians there who could handle an office remodel.

I'm curious as to why you are asking these questions.

 

[shawn73]

Re: type NM-B Wire in Factory

We have a utility person who builds our offices and has for some time. The office now has walls and wire but no drywall. He always wires them with NM. Certain individuals were arguing that it was not to code, so I want to find out if they are correct because I am one of the two electricians in our shop. We don't wire offices because we don't have time for that kind of work. I would just like to know for my own knowledge. I spent some time reading the NEC, but thought this would be an easy one for someone at mikeholt.com! Thanks

 

[peter d]

Re: type NM-B Wire in Factory

Shawn,

What if there were no wires in the ceiling but there was a drop ceiling?

If the cable runs are entirely enclosed within walls and do not go into the ceiling, then NM is fine. This would be impossible since there would have to be lighting in these offices.
In that case, a transition to another method like MC cable would be necessary.

If the ceiling is drywalled, then NM is acceptable.

 

[guesseral]

Re: type NM-B Wire in Factory

I don't see the problem with NM cable IF it is only run in the walls and not above the ceiling. Everything dropped into the walls from the ceiling area or comming from the walls say to a light could not be NM cable. Depending on the size of the office area this may or may not be worth it.
I have done several office spaces in NM cable prior to the 2002 code as long as they were not plenum ceilings.
Altho many people were upset when the 2002 code allowed NM cable to be used in more places, I think it took away more practical uses than it added! Of course this is just my take.

 

[jtester]

Re: type NM-B Wire in Factory

shawn73
The issue isn't so much that you are wiring a space you call an office, as it is whether the space is adequately separated by fire walls to not be considered part of the factory. Just because someone calls it an office doesn't mean the building codes see it as a place NM is permitted.
You should turn to the building code applicable in your area to figure out if the separation walls are substantial enough to allow NM.
Jim T

 

[electricmanscott]

Re: type NM-B Wire in Factory

"Describe MC.(???)" * This NEC? Forum is for those in the electrical and related industries.
Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice
Moderators?

 

[don_resqcapt19]

Re: type NM-B Wire in Factory

Inside our automotive factory we are building a new office.

What type of construction does the building require for the factory itself? If the building codes require Type I or II construction, then NM is not permitted in the building. 334.10(3)
Don

 

[guesseral]

Re: type NM-B Wire in Factory

__________________________________________________
What type of construction does the building require for the factory itself? If the building codes require Type I or II construction, then NM is not permitted in the building. 334.10(3)
Don
__________________________________________________

When I saw build an office for an industrial facility I assumed an addition outside of the facility I missed inside.

But is your statement true? Article 334.10 states other structures permitted to be of types III. IV, and V ...... Per article 100 the definition of a structure is "that which is built or constructed" You could build or construct inside or outside.
I am not doubting you statement, just wondering if its the intent to include the entire building or if, segmented portions of the building could use different wiring methods. The latter would be my interpretation! Of course fire wall separation would be required.

 

[apauling]

Re: type NM-B Wire in Factory

there is a problem here that is outside the NEC. If the type of building (type 1,2,3,4,5) is required because of the details of the occupancy, size, usage, setbacks, fire protection, hazards, etc., the type of construction for the office may not be permitted. if the office is being inspected by a jurisdiction, it wll have had to go thru plan checks, and the details of the wiring should should be noted on the plans, and inspected.

if the construction inside the industrial facility is not being inspected, it may not even be code compliant construction in the first place.

there are an immense amount of details to check before this issue can be passed as either code compliant or not.

paul

 

[ryan_618]

Re: type NM-B Wire in Factory

Factories are almost always an unlimited area building, due to tight fire sprinkler requirements and area frontage. Due to that, the building is probably type V-B (wood frame and non-rated). Just becasue the building looks like a type I doesn't mean it is...for example, a typical Super Walmart is a V-B building, despite the fact that there is no wood in it at all, and probably meets the description of type I!.

 

[apauling]

Re: type NM-B Wire in Factory

automotive factory, type 5?

open flame, welding, at least a one hour seperation on all exposed surfaces, including ceiling if area above office is exposed to the industrial facility. real one hour. too many variables and nothing can be assumed.

paul

 

[ryan_618]

Re: type NM-B Wire in Factory

Originally posted by apauling:
automotive factory, type 5?

open flame, welding, at least a one hour seperation on all exposed surfaces, including ceiling if area above office is exposed to the industrial facility. real one hour. too many variables and nothing can be assumed.

paul

Not if it is sprinklered and has sixty feet of property frontage. I'm not saying they built it with wood, I'm just saying they would be allowed to build it with wood. The prohibitation of NM is for buildings required to be type I or II.

 

[apauling]

Re: type NM-B Wire in Factory

ryan; you are probably under the ibc, but i am still in ubc land. there are no unlimited area auto factories of type 5 construction allowed under the 97 ubc (CBC). unlimited area construction requires a type 1 construction and that type is required throughout. all other types of construction are limited in all types of occupancies.

paul

 

[james wuebker]

Re: type NM-B Wire in Factory

Shawn, I don't think there's a problem using NM wire as long they stay in the walls and don't come in the ceiling. That is going to make it hard to get your power feeds to them. The best way is to use MC cable. With an office in a factory they are going to want something installed down the road. More telephone lines, lighting and ect. I would also put extra boxes in the office and stub conduit through your wall header so it would be in your ceiling area. This would make it easier down the road. In most of our offices through-out my factory all to runs are stub up and tie together. This makes it easier to add to if needed. Good luck with your project.
Jim