Romex in a Commercial building

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StreamlineGT

Senior Member
I have a job to do in a commercial single story building, wiring some outside A/C units and some air handlers. The wiring method used in the building when it was built is Romex. There is drop ceiling in the tenant spaces, and no sheetrock above, just insulation and then the attic. Is there anything preventing me from running Romex for new wiring? For some reason I thought there was a code change, and I am not a big commercial guy, mostly resi. Thanks in advance.

Brendon
 

growler

Senior Member
Location
Atlanta,GA
StreamlineGT said:
There is drop ceiling in the tenant spaces, and no sheetrock above, just insulation and then the attic. Is there anything preventing me from running Romex for new wiring?

You can't run Romex (NM) but there is nothing to prevent you from running MC cable. It's just about as easy to run and not really that much more expensive.

If you are going to do commercial get good at running MC cable.
 

C3PO

Senior Member
Location
Tennessee
iwire said:
You can no longer run NM above suspended ceilings in commercial occupancies.

This is true, but around here in most cases the AHJ will let us run NM for new stuff if it is in an existing building that already has NM above the drop ceiling.
I would ask my AHJ if I were you.
 

charlie

Senior Member
Location
Indianapolis
iwire said:
You can no longer run NM above suspended ceilings in commercial occupancies.
It is too bad this is not in Indiana. The Indiana Electrical Code states, "Sec. 19. In SECTION 334.12(A), delete Item (2) without substitution." :)
 

peter d

Senior Member
Location
New England
My views on this subject are pretty well known by now, so I'll just say that I have never seen one piece of evidence supporting the "safety aspect" of this prohibition. And I think Massachusetts and Indiana have it right with their amendments. :)
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
C3PO said:
This is true, but around here in most cases the AHJ will let us run NM for new stuff if it is in an existing building that already has NM above the drop ceiling.
I would ask my AHJ if I were you.


same here.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
wireperson said:
one time I rejected one job ,because the GC wanted me to use romex in an office addition.

its a good idea to let the inspections dept tell the GC they will approve or disapprove of something before completely turning it down. you can tell them it doesn't meet code, but tell them you'll check w/ the inspections dept for verification. i've only had that happen a couple of times.
 

wbalsam1

Senior Member
Location
Upper Jay, NY
Originally Posted by iwire
You can no longer run NM above suspended ceilings in commercial occupancies.

C3PO said:
This is true, but around here in most cases the AHJ will let us run NM for new stuff if it is in an existing building that already has NM above the drop ceiling.
I would ask my AHJ if I were you.

I hope this AHJ you are talking about actually has the statutory authority to waive the rules. In NYS, the electrical inspector can not make the decision to do as you say. All new work must conform to the code.
Whether I agree with the logic of the code provision or not, I agree that an inspector should never take it upon him/her self to waive the rules. :smile:
 

C3PO

Senior Member
Location
Tennessee
wbalsam1 said:
I hope this AHJ you are talking about actually has the statutory authority to waive the rules. In NYS, the electrical inspector can not make the decision to do as you say. All new work must conform to the code.
Whether I agree with the logic of the code provision or not, I agree that an inspector should never take it upon him/her self to waive the rules. :smile:

Not 100% sure on the authority part, but every time i have been allowed to do this it has just been minor things added.
 

iwire

Moderator
Staff member
Location
Massachusetts
C3PO said:
Not 100% sure on the authority part, but every time i have been allowed to do this it has just been minor things added.

Regardless of the inspectors lack of carrying I would break out the MC in those situations. No matter what the inspector lets you do it is still a violation with your name on it until it is removed.

I see no reason to put my neck out to save the customer the cost difference between NM and MC. :smile:
 

ultramegabob

Senior Member
Location
Indiana
Would it be a violation to run your NM through the trusses and then set a j-box transitioning to MC to run through the suspended ceiling? I believe the intent of the code is to keep the NM from being damaged by the sharp edges of the ceiling and lack of good methods to support NM above a suspended ceiling. I guess what Im asking is the NM inside the trusses a violation? they are above the suspended ceiling:-?
 

iwire

Moderator
Staff member
Location
Massachusetts
ultramegabob said:
Would it be a violation to run your NM through the trusses and then set a j-box transitioning to MC to run through the suspended ceiling?

334.10(3) pretty much requires all NM not in a dwelling unit to be concealed by a 15 min wall finish.

So in some commercial spaces you could use NM in the walls and transition to MC or pipe where exposed.
 

ultramegabob

Senior Member
Location
Indiana
if the suspended ceiling has a 15 minute rating, does there have to be any other barrier on the bottom of the trusses to protect the NM? Is a suspended ceiling a finished surface?
 
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