romex

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Dennis Alwon

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Chapel Hill, NC
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Retired Electrical Contractor
Look at 334.10 and understand that NM cannot be used in a suspended ceiling in a commercial building whether it is a plenum or not.

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.
(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.
FPN No. 1: Types of building construction and occupancy classifications are defined in NFPA 220-2006, Standard on Types of Building Construction, or the applicable building code, or both.
FPN No. 2: See 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.
 
Location
Maine
Even here in Maine you now cannot use nm in suspended ceilings in commercial buildings. Until the last code cycle the state was allowing it.

I take it back -- Just looked it up and the amendment was adopted with the 2008 code.
 
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220/221

Senior Member
Location
AZ
can romex be used in a commercal building


Not in civilized parts of the country :grin:



In commercial work here, line voltage requires pipe&wire, MC, flex etc. The exception here is low voltage (lights with a 12V remote transformer for example). In those cases NM is approved.
 

220/221

Senior Member
Location
AZ
Yes but I have never read it.

From my observation, I'm guessing it's been that way since the early 60's.


Until the internet, I assumed it was national code. :-?
 

iwire

Moderator
Staff member
Location
Massachusetts
Welcome to the forum

That depends on type of building

Close, not so much the type of building constructed but the kind of building that could have been constructed.

For instance you can run NM in a Type I or Type II building as long as the code would have allowed that same building to be Type III, IV or V.
 

Riograndeelectric

Senior Member
funny you should ask this question. about 15 years ago I was doing a tenet finish remodel on a 6 story building built ion the 1970s.. The whole building was wired with Romex. even the 277V lights had Romex feeding them. Inspector made us tear it all out and use MC cable the Management company was pissed and chewed my boss way down on his price to rewire the space. the same building also had ZINSCO Panels. / 120/208 277/480V

it was kind of fun when our tracer could not identify a circuit so we tried shorted the hot to ground and never could get the breaker to trip all we could hear was a loud hum and some vibration in the wall from the circuit shorting. I think I could have actually welded with this circuit with out tripping the breaker.

mu opion is Romex should not be allowed in commercial building where the building classification allows it


Cameron
 

iwire

Moderator
Staff member
Location
Massachusetts
even the 277V lights had Romex feeding them.

NM is rated 600 volts.

it was kind of fun when our tracer could not identify a circuit so we tried shorted the hot to ground and never could get the breaker to trip all we could hear was a loud hum and some vibration in the wall from the circuit shorting. I think I could have actually welded with this circuit with out tripping the breaker.

First off you where doing something incredibly stupid, that is a good way to get burned, shocked or maybe start a fire in a wall.

Second off the fact that it was NM has absolutely noting to do with how long the breakers took to trip.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Close, not so much the type of building constructed but the kind of building that could have been constructed.

For instance you can run NM in a Type I or Type II building as long as the code would have allowed that same building to be Type III, IV or V.

I did work very short time for an EC that was doing small office buildings in romex. We parted company very fast as his workmanship was very pathetic. He had no real code backing or training will assume got license 40 years ago. I usually can tell in a few days what kind of company they are. Clue to this 1 was only 1 old van and a junk car pulling a trailer.
 

peter d

Senior Member
Location
New England
Not in civilized parts of the country :grin:



In commercial work here, line voltage requires pipe&wire, MC, flex etc. The exception here is low voltage (lights with a 12V remote transformer for example). In those cases NM is approved.

Thankfully we used common sense in my part of the country, that is, until the NEC changed. :cool: There are literally thousands of commercial use buildings including supermarkets, high rise apartment buildings, office parks, etc wired with NM cable here in New England.
 

electricmanscott

Senior Member
Location
Boston, MA
Thankfully we used common sense in my part of the country, that is, until the NEC changed. :cool: There are literally thousands of commercial use buildings including supermarkets, high rise apartment buildings, office parks, etc wired with NM cable here in New England.


Sure but look at the result....:roll:
graveyard-vignette.jpg
 

Riograndeelectric

Senior Member
NM is rated 600 volts.



First off you where doing something incredibly stupid, that is a good way to get burned, shocked or maybe start a fire in a wall. I was a green Journeyman & still learning not that this is an excuse . Today I know better than to try to short out a circuit to find the breaker. my mind at the time was thinking this was no big deal because hopefully the Breaker would trip so we could ID the circuit. since the circuit tracer was not able to locate the circuit or I may have been using the tracer wrong.

it was the fact that they were zinsco breakers. Romex was located above suspend ceiling used as return air plenum.

Second off the fact that it was NM has absolutely noting to do with how long the breakers took to trip.


If I did something like this today I would need to have my Brain examined for doing such dumb move.
you are right to say I was doing something stupid.
Cameron
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
If I did something like this today I would need to have my Brain examined for doing such dumb move.
you are right to say I was doing something stupid.
Cameron

You wer working under an ID 10 T

you not only could been seriously hurt or killed but might been visited by fire department
A zinsco might never trip. It is a very bad practice to even do on good breakers. If you don't know where the breaker is you can't be even sure it has one.
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
Thankfully we used common sense in my part of the country, that is, until the NEC changed. :cool: ...
But the change that ended up prohibiting the use of NM above drop ceilings in commercial building was what the NM supporters gave up to get rid of the three story limit that was in previous codes.
 

peter d

Senior Member
Location
New England
But the change that ended up prohibiting the use of NM above drop ceilings in commercial building was what the NM supporters gave up to get rid of the three story limit that was in previous codes.


True. However, Mass. amended the NEC change to continue to allow the practice. MA has some of the least strict rules for NM cable in the country.


I could be wrong, but I think MA also had an unlimited height requirement on NM cable when the NEC had the rule in place. I think the rule was that the cable could not go from floor to floor or something like that. I'm not sure though and just shooting from the hip, and we all know where that gets you.
 
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