NM cable in nonmetalic flex

Status
Not open for further replies.

S King

New member
Location
Dunn, NC
Does the NEC prohibit the use of NM cable in liquidtight flexible nonmetallic conduit? An example would be using NM cable from a disconnect to an air conditioning unit.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: NM cable in nonmetalic flex

S King said:
Does the NEC prohibit the use of NM cable in liquidtight flexible nonmetallic conduit? An example would be using NM cable from a disconnect to an air conditioning unit.

I seem to recall the latest (2005) version of the code allows NM to be run in a raceway. Previous to this code version, running it in any raceway was not permitted (except where used for physical protection from damage).
 

tonyi

Senior Member
It wasn't that it was prohibited pre-05' its that it wasn't explicitly permitted (quite different notions). I would have argued that it was implied pre-05' by the mention of cable assemblies in the conduit fill tables.
 

allenwayne

Senior Member
334.12 does not list outdoors.Not to be used where subject to excessive moisture or dampness.In liquid tight flex with approved liquid tight connectors doesn`t constitute a damp or moist location,does it???
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
allenwayne said:
In liquid tight flex with approved liquid tight connectors doesn`t constitute a damp or moist location,does it???
It does if the flex is outdoors. Inside a raceway is not a "location". Wire inside even a watertight enclosure or raceway located outdoors is still outdoors.
 

allenwayne

Senior Member
Larry can you show me where it states that within liquid tite out doors it is considered a damp / moist/ wet area???The NEC does show us that if in pipe and underground the conductors must be rated for a wet location,but I have tried to find where it states that if within flexible non metalic conduit that is not installed underground the conductors must be wet location rated.
100 - Watertight.Constructed so that moisture will not enter the enclosure under specified test conditions
100 - Weatherproof.Constructed or PROTECTED so that exposure to the weather will not interfere with succesful operation
356.10 (2)Where protection of the contained conductors is required from vapors,liquids,or solids
All I have read says NM in LFNMC is fine :wink:
 

dlhoule

Senior Member
Location
Michigan
allenwayne said:
Larry can you show me where it states that within liquid tite out doors it is considered a damp / moist/ wet area???The NEC does show us that if in pipe and underground the conductors must be rated for a wet location,but I have tried to find where it states that if within flexible non metalic conduit that is not installed underground the conductors must be wet location rated.
100 - Watertight.Constructed so that moisture will not enter the enclosure under specified test conditions
100 - Weatherproof.Constructed or PROTECTED so that exposure to the weather will not interfere with succesful operation
356.10 (2)Where protection of the contained conductors is required from vapors,liquids,or solids
All I have read says NM in LFNMC is fine :wink:
:D

334.12 Uses Not Permitted.

(A) Types NM, NMC, and NMS. Types NM, NMC, and NMS cables shall not be permitted as follows:

(1) In any dwelling or structure not specifically permitted in 334.10(1), (2), and (3)

(2) Exposed in dropped or suspended ceilings in other than one- and two-family and multifamily dwellings

(3) As service-entrance cable

(4) In commercial garages having hazardous (classified) locations as defined in 511.3

(5) In theaters and similar locations, except where permitted in 518.4(B)

(6) In motion picture studios

(7) In storage battery rooms

(8) In hoistways or on elevators or escalators

(9) Embedded in poured cement, concrete, or aggregate

(10) In hazardous (classified) locations, except where permitted by the following:

a. 501.10(B)(3)

b. 502.10(B)(3)

c. 504.20

(B) Types NM and NMS. Types NM and NMS cables shall not be used under the following conditions or in the following locations:

(1) Where exposed to corrosive fumes or vapors

(2) Where embedded in masonry, concrete, adobe, fill, or plaster

(3) In a shallow chase in masonry, concrete, or adobe and covered with plaster, adobe, or similar finish

(4) Where exposed or subject to excessive moisture or dampness

IMO that about covers it. You will have condensation in an outdoor installation. :)
 

Ragin Cajun

Senior Member
Location
Upstate S.C.
Maybe it's too close to going home, but I don't consider inside a piece of LIQUID TITE flex or inside an outdoor enclosure as being "exposed or subject to excessive moisture or dampness."
 

colosparker

Senior Member
dlhoule said:
IMO that about covers it. You will have condensation in an outdoor installation. :)


Wouldn't the air inside the piece of liquidtight have to be considerably cooler than air on the outside of the liquidtight in order for condensation to appear? And wouldn't the condensation form on the outside of the liquidtight rather than inside the liquidtight? Enquiring minds want to know :D
 

colosparker

Senior Member
The rule we used to use was you always strip the romex back far enough so that it does not show past the flex connectors. :wink:

Who has THHN on a residential work truck for crying out loud.
 

Towzzer

Member
pick up a roll of red green white and black, put them on a pole in your truck, and your set , you never know when you need the stuff
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
allenwayne said:
Larry can you show me where it states that within liquid tite out doors it is considered a damp / moist/ wet area???The NEC does show us that if in pipe and underground the conductors must be rated for a wet location,but I have tried to find where it states that if within flexible non metalic conduit that is not installed underground the conductors must be wet location rated.
Allen, you seem to be under the impression that watertight raceways are watertight. :roll:
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Towzzer said:
pick up a roll of red green white and black, put them on a pole in your truck, and your set , you never know when you need the stuff

Almost with you on this sept for no reason for 2 non grounded colors.Red or black or even orange is fine for a house.No phases to worry about.
 

marinesgt0411

Senior Member
colosparker said:
The rule we used to use was you always strip the romex back far enough so that it does not show past the flex connectors. :wink:

Who has THHN on a residential work truck for crying out loud.

that said my boss asked me Don't you have that on your truck?Told my boss that I needed a 45 foot trailer behind my van so I could carry all the diferant types of conduit, fittings,devices,and wire that I might need.
 
Status
Not open for further replies.
Top