14 romex commercial

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Cletis

Senior Member
Location
OH
Can i run 14 gauge romex in a 4 family wood framed building for lighting?


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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Can i run 14 gauge romex in a 4 family wood framed building for lighting?


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Why are you calling this commercial? In general you can but nm cable is based on the classification of the building

334.10 Uses Permitted. Type NM, Type NMC, and Type
NMS cables shall be permitted to be used in the following,
except as prohibited in 334.12:
(1) One- and two-family dwellings and their attached or
detached garages, and their storage buildings.
(2) Multi-family dwellings permitted to be of Types III, IV,
and V construction.
(3) Other structures permitted to be of Types III, IV, and V
construction. 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.
 

Cletis

Senior Member
Location
OH
thats what I was looking for. The big question is where did this "myth" of everything needs to be run in 12 come from ??? Everyone around here electricians and engineers think you "have to" run 12 in commercial.

4 family here is rated commercial
 

peter d

Senior Member
Location
New England
thats what I was looking for. The big question is where did this "myth" of everything needs to be run in 12 come from ??? Everyone around here electricians and engineers think you "have to" run 12 in commercial.

Ignorance of what the code actually says, but a lot of it has to do with job specs requiring #12 minimum for "commercial".
 

rcarroll

Senior Member
thats what I was looking for. The big question is where did this "myth" of everything needs to be run in 12 come from ??? Everyone around here electricians and engineers think you "have to" run 12 in commercial.

4 family here is rated commercial
Not counting residential, I'd say the "myth" comes from the job specs. Every commercial job I've wired, #12 cu. was the minimum size conductor. JMHO
 

JFletcher

Senior Member
Location
Williamsburg, VA
Yep, same reason you see so many 20 amp duplex receps in "commercial".

Mounted ground up with stainless steel plates as well.

eta:

thats what I was looking for. The big question is where did this "myth" of everything needs to be run in 12 come from ??? Everyone around here electricians and engineers think you "have to" run 12 in commercial.

4 family here is rated commercial

It may come from derating too; just more headroom with 12ga. Also, MC cable that is 12ga has some bundling advantages that 14 doesnt, specifically under 310.15(B)(2) exception #5.
 
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kwired

Electron manager
Location
NE Nebraska
Mounted ground up with stainless steel plates as well.

eta:



It may come from derating too; just more headroom with 12ga. Also, MC cable that is 12ga has some bundling advantages that 14 doesnt, specifically under 310.15(B)(2) exception #5.
You base this on something on other then 2014 NEC? For 2014 I think you are referring to 310.15(B)(3)(a)(4), (B)(2) is ambient temperature correction factors in 2014.
 
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