Please help! Max length of Liquid tight flex
- Thread starter bamiller
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ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Please help! Max length of Liquid tight flex
metallic or non-metallic? 356.12 limits LFNC to six feet, with a couple of exceptions. 350.12 does not address a length for LFMC. He is quoting the securing, as you stated.
metallic or non-metallic? 356.12 limits LFNC to six feet, with a couple of exceptions. 350.12 does not address a length for LFMC. He is quoting the securing, as you stated.
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
Is this LFMC Article 350 or LFNC Article 356.
Just curious, where and how is it being used?
Russ
Is this LFMC Article 350 or LFNC Article 356.
Just curious, where and how is it being used?
Russ
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
OOPs I see LFNC.
OOPs I see LFNC.
Re: Please help! Max length of Liquid tight flex
As far as I can see in Article 350 of the NEC, there is no maximum length specified. I know I have used it in lengths of up to 100 feet and even buried it. It has to be the inspector is misquoting the code or using his jurisdictional authority. It may aggravate him to be called on it and make more problems than its worth. Can you not get within 3 feet of what you're installing so you can use the flex the way he wants it used? Just thinking sometimes you have to pick your battles and this may not be worth arguing over. Have a great day, Leamon
As far as I can see in Article 350 of the NEC, there is no maximum length specified. I know I have used it in lengths of up to 100 feet and even buried it. It has to be the inspector is misquoting the code or using his jurisdictional authority. It may aggravate him to be called on it and make more problems than its worth. Can you not get within 3 feet of what you're installing so you can use the flex the way he wants it used? Just thinking sometimes you have to pick your battles and this may not be worth arguing over. Have a great day, Leamon
- Location
- Massachusetts
Re: Please help! Max length of Liquid tight flex
350.2 Definition.
Liquidtight Flexible Metal Conduit (LFMC). A raceway of circular cross section having an outer liquidtight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core with associated couplings, connectors, and fittings for the installation of electric conductors.
OR
ARTICLE 356 Liquidtight Flexible Nonmetallic Conduit: Type LFNC
356.2 Definition.
Liquidtight Flexible Nonmetallic Conduit (LFNC). A 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 covers, 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 LFNC-C.
ARTICLE 350 Liquidtight Flexible Metal Conduit: Type LFMC
350.2 Definition.
Liquidtight Flexible Metal Conduit (LFMC). A raceway of circular cross section having an outer liquidtight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core with associated couplings, connectors, and fittings for the installation of electric conductors.
OR
ARTICLE 356 Liquidtight Flexible Nonmetallic Conduit: Type LFNC
356.2 Definition.
Liquidtight Flexible Nonmetallic Conduit (LFNC). A 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 covers, 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 LFNC-C.
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
I've read 356 .10,.12 and.30 back and forth, and it looks like you can have up to six feet (356.12 (3)) but it would have to be straped, 356.30.
Russ
I've read 356 .10,.12 and.30 back and forth, and it looks like you can have up to six feet (356.12 (3)) but it would have to be straped, 356.30.
Russ
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
I,ve been allowing longer than 3ft whips of LFMC (We don't allow LFNC) for a long time. Guess maybe I been a little lenient
and I thought I was tough!
I,ve been allowing longer than 3ft whips of LFMC (We don't allow LFNC) for a long time. Guess maybe I been a little lenient
and I thought I was tough!
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Please help! Max length of Liquid tight flex
Why wouldn't you allow it?Originally posted by russ:
I,ve been allowing longer than 3ft whips of LFMC (We don't allow LFNC) for a long time. Guess maybe I been a little lenient
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
It's possible it could be used, but not likely.
From the Chicago Code
PART B. LIQUIDTIGHT FLEXIBLE NONMETALLIC CONDUIT
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.
It's possible it could be used, but not likely.
From the Chicago Code
PART B. LIQUIDTIGHT FLEXIBLE NONMETALLIC CONDUIT
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.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Please help! Max length of Liquid tight flex
If you were to run an EGC in the liquidtight (metallic or nonmetallic), there is no limit to the length it is installed.
LFNC-B is the gray colored type that most of see today. The UL White Book (General Information for Electrical Equipment) describes the different types and permitted listings.
Pierre
If you were to run an EGC in the liquidtight (metallic or nonmetallic), there is no limit to the length it is installed.
LFNC-B is the gray colored type that most of see today. The UL White Book (General Information for Electrical Equipment) describes the different types and permitted listings.
Pierre
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Please help! Max length of Liquid tight flex
Pierre, take a look at 356.12 again. As you'll notice, it is not an EGC issue. See also 250.118 for types of EGC's permitted. The only exceptions (I don't have my code here, but I think I remember) are: 1) if you absolutley need it for flexibility or 2) If it somes pre-wired in a coil of some sort.
Pierre, take a look at 356.12 again. As you'll notice, it is not an EGC issue. See also 250.118 for types of EGC's permitted. The only exceptions (I don't have my code here, but I think I remember) are: 1) if you absolutley need it for flexibility or 2) If it somes pre-wired in a coil of some sort.
curt swartz
Electrical Contractor - San Jose, CA
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Re: Please help! Max length of Liquid tight flex
Ryan
Look at 356.10(5). I believe there is an error in 356.12(3) since there isn't a 356.100(5). It should be 356.10(5)
Ryan
Look at 356.10(5). I believe there is an error in 356.12(3) since there isn't a 356.100(5). It should be 356.10(5)
A
a.wayne3@verizon.net
Guest
Re: Please help! Max length of Liquid tight flex
As long as it is strapped in accordance with nec
IE: within required distances of box and between straps ,there is no max. distance,just a max. length of whip 6 ft.
After all it is conduit.......
As long as it is strapped in accordance with nec
IE: within required distances of box and between straps ,there is no max. distance,just a max. length of whip 6 ft.
After all it is conduit.......
russ
Senior Member
- Location
- Burbank IL
Re: Please help! Max length of Liquid tight flex
I'm A convert!
I believe Curt is right about the miss print on the code number.
You guys have figured out the whip length.
My vote.
A six foot whip (or less) with a proper ground should be acceptable, more than six foot the straping comes in.
Russ
I'm A convert!
I believe Curt is right about the miss print on the code number.
You guys have figured out the whip length.
My vote.
A six foot whip (or less) with a proper ground should be acceptable, more than six foot the straping comes in.
Russ
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Please help! Max length of Liquid tight flex
The NEC is a difficult article enough to read and fully understand without misprints like this!!! Oh well, we learn once again.
Nice catch on the misprint.
Ditto!!!
The NEC is a difficult article enough to read and fully understand without misprints like this!!! Oh well, we learn once again.
Nice catch on the misprint.
Re: Please help! Max length of Liquid tight flex
Well, I agree partially. Yes, the errata indicates that the reference in 356.12(3) should be to 356.10(5) rather than 356.100(5), but this only allows LFNC-B to be used in lengths longer than 6'. I believe other types of LFNC are limited by 356.12(3) to lengths of 6' unless a longer length is approved as essential for a required degree of flexibility. Since LFNC-B is available, why would it ever be necessary to approve the use of another type in lengths longer than 6'?
Well, I agree partially. Yes, the errata indicates that the reference in 356.12(3) should be to 356.10(5) rather than 356.100(5), but this only allows LFNC-B to be used in lengths longer than 6'. I believe other types of LFNC are limited by 356.12(3) to lengths of 6' unless a longer length is approved as essential for a required degree of flexibility. Since LFNC-B is available, why would it ever be necessary to approve the use of another type in lengths longer than 6'?
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