resistance
Senior Member
- Location
- WA
For a residential dwell., what is the highest floor level (3rd floor, or etc) that you can use NM-B?
Floor level
- Thread starter resistance
- Start date
- Status
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Floor level
334.10 allows NM to be used in dwellings with any amount of floors as the restrictions were removed in "2002" NEC but on multi unit dwellings it will depend upon what type of fire rating the building has. It is permitted in Types III, IV, and V construction.
Here is an FPN that tells us where to get this info:
Edited to add the reference to the "99" NEC
[ December 23, 2004, 02:26 AM: Message edited by: hurk27 ]
334.10 allows NM to be used in dwellings with any amount of floors as the restrictions were removed in "2002" NEC but on multi unit dwellings it will depend upon what type of fire rating the building has. It is permitted in Types III, IV, and V construction.
Here is an FPN that tells us where to get this info:
But if your area is still under the "1999"NEC then you might not be able to install it in a dwelling over three floors as 336-5 will not allow it.
Edited to add the reference to the "99" NEC
[ December 23, 2004, 02:26 AM: Message edited by: hurk27 ]
electricmanscott
Senior Member
- Location
- Boston, MA
- Occupation
- Massachusetts Master Electrician, one man show.
Re: Floor level
Top floor.
Top floor.
resistance
Senior Member
- Location
- WA
Re: Floor level
Exactly! Thanks! Had to re-confirm myself!
Exactly! Thanks! Had to re-confirm myself!
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Floor level
I was told once that NM was never intended to be restricted to just three floors in one and two family dwellings in the "1999" NEC, 336-4 1. clearly allows it in one and two-family dwellings. The restriction was in 336-4 2. which was for Multifamily dwellings and other structures. and in 336-5 in Multifamily dwellings and other structures is where it was restricted to just three floors. But many inspectors were interpiting "other structures" to not allow it in one and two family dwellings above three floors. But "other structures" was meant to be other than a dwelling as in commercial buildings.
In the "2002" NEC they still had the same wording which didn't clear this up as it still say's in 334.10 (1) that it is permitted to be used in one and two-family dwellings. But they changed the requirements for Multifamily dwellings and other structures to allow it if the building is of Types III, IV, and V construction.
We still have inspectors who think it is not allowed in one and two-family dwellings. Just thought I would throw this in.
I was told once that NM was never intended to be restricted to just three floors in one and two family dwellings in the "1999" NEC, 336-4 1. clearly allows it in one and two-family dwellings. The restriction was in 336-4 2. which was for Multifamily dwellings and other structures. and in 336-5 in Multifamily dwellings and other structures is where it was restricted to just three floors. But many inspectors were interpiting "other structures" to not allow it in one and two family dwellings above three floors. But "other structures" was meant to be other than a dwelling as in commercial buildings.
In the "2002" NEC they still had the same wording which didn't clear this up as it still say's in 334.10 (1) that it is permitted to be used in one and two-family dwellings. But they changed the requirements for Multifamily dwellings and other structures to allow it if the building is of Types III, IV, and V construction.
We still have inspectors who think it is not allowed in one and two-family dwellings. Just thought I would throw this in.
- Status