LTFNMC vs. LTFMC

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mdshunk

mdshunk

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Assuming you pull a ground and there aren't any print specs, is there any reason to run LTFMC (Sealtite) as a preferred raceway over LTFNMC (Carflex)? Are there any NEC requirements someplace that would permit LTFMC but preclude the use of LTFNMC?
 
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mdshunk said:
Assuming you pull a ground and there aren't any print specs, is there any reason to run LTFMC (Sealtite) as a preferred raceway over LTFNMC (Carflex)? Are there any NEC requirements someplace that would permit LTFMC but preclude the use of LTFNMC?
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I don't have my code book near me , and I can't think of any requirements.

But if for some reason you wanted to enclose a GEC , it would be much easier to install it in LTFNMC. If you put it in LTFMC you would have to bond both ends to the GEC (assuming the inside is ferrous metal) , more steps, more requirements, more cost. Also installing the GEC in this method may reduce the effect of the GEC.

ibew441dc
 
I kind of feel like I'm cheating when I use LTFNMC but I can't justify my fear. I see more and more of it being used and would assume that it is a legal, listed raceway. I guess I'm from the old school when all we ever used was LTFMC.
 
m73214 said:
I kind of feel like I'm cheating when I use LTFNMC but I can't justify my fear. I see more and more of it being used and would assume that it is a legal, listed raceway. I guess I'm from the old school when all we ever used was LTFMC.
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Why would you feel like cheating? Its a listed wiring method... I don't think I can remember the last time I used sealtite...
 
From the Chicago code.

PART B. LIQUIDTIGHT FLEXIBLE NONMETALLIC CONDUIT
18-27-351.22. Definition.
Liquidtight flexible nonmetallic conduit is a listed raceway of circular cross section of various types as follows:
(1) A smooth seamless inner core and cover bonded together and having one or more reinforcement layers between the core and
cover, designated as Type LFNC-A
(2) A smooth inner surface with integral reinforcement within the conduit wall, designated as Type LFNC-B
(3) A corrugated internal and external surface without integral reinforcement within the conduit wall, designated as Type LFNC-C
18-27-351.23. Use.
(a) Permitted. Listed liquidtight flexible nonmetallic conduit shall be permitted to be used only in corrosive areas, with special
permission, in installations where no suitable alternative wiring material can be used.
FPN: Extreme cold may cause some types of nonmetallic conduits to become brittle and therefore more susceptible to damage from physical contact.
 
Marc,

LTFNC has to be supported every 3ft. vs. 4.5 for LTFC, also 356.10 fpn

warning about extremily cold temps. I guess I'm old school also, I can't

remember ever installing a single peice of LTNMC. Just throw the money out

the window!!!
 
stickboy1375 said:
Why would you feel like cheating? Its a listed wiring method... I don't think I can remember the last time I used sealtite...
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I guess I'm just set in my ways but I am buying those pre assembeled A/C whips and like them a lot hence my first encounter vwith LTFNMC.
 
The reason I'm asking is because even though I'm not particularly old, I was trained really old-school. I agree that using LTFNMC does somehow feel like "cheating", but it seems like LTFMC and LTFNMC are identical in the eyes of the code. There is a pretty nice price disparity that makes Carflex and the associated fittings more attractive when compared to Sealtite. The fact that Sealtite fittings tend to rust and look ugly over time makes Carflex more appealing also. I just sorta wanted to make sure that before I take the leap away from Sealtite, that there isn't some instance where I must use LTFMC and can't use LTFNMC. 517 locations are the only thing that came to mind, but it's not too often you need flex in 517 areas.
 
m73214 said:
I guess I'm just set in my ways but I am buying those pre assembeled A/C whips and like them a lot hence my first encounter vwith LTFNMC.
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How much do you pay for those? I was buying EPCO brand AC whips, until I realized that I'm paying just shy of 20 bucks for them. I can make a heck of a lot of AC whips from Carflex scraps and end rolls of #10 and #8 for 20 bucks. No more pre-made AC whips for me.
 
The labor to build them must be free.:rolleyes:

Tom

I build them if I have scraps or they are #12/#14, and Larger than #8's.
 
It's not code, but it is my companies policy. We use Carflex for residential AC whips. Any commercial exterior work is Sealtight. We feel the connectors hold up longer.

In our hot climate, Carflex connectors fall apart in a a couple of years. Sealtight connectors last much longer when exposed to extreme weather conditions.

I maintain most of the billboards in this area. The billboards bake in the sun. I routinely see Sealtight outlasting Carflex.

Just my humble opinion.
 
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