LFMC

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David M

Member
Location
San Diego
Hi folks, new here. The confusion over the alleged "six foot rule" drives me crazy. The way I read the code there is no limit to the allowable length of LFMC so long as the total bend does not exceed 360* and the raceway contains an equipment grounding conductor. Does everyone agree (except you NYC guys) ? I'm having an issue with this right now so I'm looking for all the support I can get :D TIA for your input.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Hi folks, new here. The confusion over the alleged "six foot rule" drives me crazy. The way I read the code there is no limit to the allowable length of LFMC so long as the total bend does not exceed 360* and the raceway contains an equipment grounding conductor. Does everyone agree (except you NYC guys) ? I'm having an issue with this right now so I'm looking for all the support I can get :D TIA for your input.


The confusion may be the grounding aspect of the install. If the lfmc is under 6' and the overcurrent protective device is 20 amp then the lfmc is compliant as an equipment grounding conductor. Otherwise a separate equipment grounding conductor must be used and there is no limit as you stated.

250.118(7) Flexible metallic tubing where the tubing is terminated
in listed fittings and meeting the following conditions:
a. The circuit conductors contained in the tubing are
protected by overcurrent devices rated at 20 amperes
or less.
b. The combined length of flexible metal conduit and
flexible metallic tubing and liquidtight flexible
metal conduit in the same ground-fault current
path does not exceed 1.8 m (6 ft).
 

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
Hi folks, new here. The confusion over the alleged "six foot rule" drives me crazy. The way I read the code there is no limit to the allowable length of LFMC so long as the total bend does not exceed 360* and the raceway contains an equipment grounding conductor. Does everyone agree (except you NYC guys) ? I'm having an issue with this right now so I'm looking for all the support I can get :D TIA for your input.

Correct as I read it also
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
I would draw attention to the UL White Book which is enforceable through Section 90.3(B):

Flexible Metal Conduit, Liquid-tight (DXHR)
USE AND INSTALLATION
This category covers liquid-tight flexible metal conduit intrade sizes 3/8
to 4 (metric designators 12 to 103) inclusive, forinstallation in accordance
with Article 350 of ANSI/NFPA 70, ‘‘National ElectricalCode’’ (NEC).
Liquid-tight flexible metal conduit is intended for use withconductors in
circuits of 600 V nominal or less. This product may also beused for installation
of conductors in motor circuits, and for electric signs andoutline lighting
in accordance with the NEC.
Liquid-tight flexible metal conduit is sunlight resistantand suitable for use
outdoors.
Where terminated in fittings investigated for grounding andwhere
installed with not more than 6 ft (total length) in anyground-return path,
liquid-tight flexible metal conduit in the 3/8 and 1/2 (12and 16) trade sizes
is suitable for grounding where used on circuits rated 20 Aor less, and the
3/4, 1 and 1-1/4 (21, 27 and 35) trade sizes are suitablefor grounding
where used on circuits rated 60 A or less. See ConduitFittings (DWTT) with
respect to fittings suitable as a grounding means.
The following are not considered tobe suitable as a grounding means:
1. The 1-1/2 (41) and larger tradesizes.
2. The 3/8 and 1/2 (12 and 16) tradesizes where used on circuits rated
higher than 20 A, or where the totallength in the ground-return path is
greater than 6 ft.
3. The 3/4, 1 and 1-1/4 (21, 27 and35) trade sizes where used on circuits
rated higher than 60 A, or where thetotal length in the ground-return
path is greater than 6 ft.
PRODUCT MARKINGS
Liquid-tight flexible metal conduit suitable for directburial is marked
‘‘Direct Burial,’’ ‘‘Burial,’’ ‘‘Dir Burial’’ or ‘‘DirBur.’’
Liquid-tight flexible metal conduit not marked with atemperature designation
or marked ‘‘60 C’’ is intended for use at temperatures notin excess
of 60°C (140°F).
Conduit intended for use in dry or oily locations at atemperature higher
than 60°C (140°F) is marked ‘‘____ C dry, 60 C wet, 70 C oilres’’ (or ‘‘____
C dry, 60 C wet, 70 C oil resistant’’) with ‘‘80’’ or‘‘105’’ inserted as the drylocations
temperature.
Conduit marked ‘‘80 C dry, 60 C wet, 60 C oil res’’ or ‘‘80C dry, 60 C oil
resistant’’ is intended for use at 80°C (176°F) and lowertemperatures in air,
and at 60°C (140°F) and lower temperatures where exposed towater, oil or
coolants.
Conduit that has not been investigated for use where exposedto oil is
marked ‘‘OIL-FREE ENVIRONMENTS ONLY.’’
ADDITIONAL INFORMATION
For additional information, see Electrical Equipment for Usein Ordinary
Locations (AALZ).
REQUIREMENTS
The basic standard used to investigate products in thiscategory is
ANSI/UL 360, ‘‘Liquid-Tight Flexible Metal Conduit.’’
UL MARK
The Listing Mark of UL on the attached tag, the reel or thesmallest unit
container in which the product is packaged, with or withoutthe UL symbol
on the product, is the only method provided by UL toidentify products
manufactured under its Listing and Follow-Up Service. TheListing Mark
for these products includes the UL symbol (as illustrated inthe Introduction
of this Directory) together with the word ‘‘LISTED,’’ acontrol number, and
the product name ‘‘Liquid-Tight Flexible Metal Conduit.’’
* * * * * * * * * * * * * * * * * * * * * * * * *
UL, in performing its functions in accordance with itsobjectives, does not
assume or undertake to discharge any responsibility of themanufacturer or
any other party. UL shall not incur any obligation orliability for any loss,
expense or damages, including incidental or consequentialdamages, arising
out of or in connection with the use, interpretation of, orreliance upon this
Guide Information.
This is often a critical issue in hazardous location installations.
 

DA72

Member
Location
Gibbstown NJ
I would draw attention to the UL White Book which is enforceable through Section 90.3(B):

This is often a critical issue in hazardous location installations.

Except I have been having a similar issue where contractors installed anacond LFMC type EF, data cut sheet clearly says unlisted product....see website

http://flexiblewiringconduits.anacondasealtite.com/category/liquid-tight-flexible-conduit


The question was sent to NJ DCA code official and this is response....

[FONT=&quot]I would agree, but 110.3(A) says if it meets the criteria listed it can be used with AHJ approval. I think based on the environment I would use 356.6 (Must Be Listed) and allow the board of appeals make the decision.[/FONT]
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Thanks for calling me on this :ashamed1:(me):thumbsup:(you) I meant 110.3(B) rather than 90.3(B). I've been loosing too much sleep recently. AHJs can approve anything they want.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
I might add though, show me the statute that gives an AHJ their "A" and I'll show you in the same statute, or a superior one, where they bear NO responsibility for poor judgement or erroneous approval. It will NOT absolve an owner/employer for any hazards of a noncompliant installation.
 

DA72

Member
Location
Gibbstown NJ
I might add though, show me the statute that gives an AHJ their "A" and I'll show you in the same statute, or a superior one, where they bear NO responsibility for poor judgement or erroneous approval. It will NOT absolve an owner/employer for any hazards of a noncompliant installation.

The contractor says install is correct Art. 501 doesn't say has to be listed, and AHJ can approve. Design engineer still haven't given answer yet, but gave impression he thought was correct. AHJ approved.

But we all know the unlisted material faux LFMC type EF isn't tested for application.

Looks like I did everything I can do pointing this out, hope my company takes my concerns serious enough to get an unbiased second opinion.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
The contractor says install is correct Art. 501 doesn't say has to be listed, and AHJ can approve. Design engineer still haven't given answer yet, but gave impression he thought was correct. AHJ approved.

But we all know the unlisted material faux LFMC type EF isn't tested for application.

Looks like I did everything I can do pointing this out, hope my company takes my concerns serious enough to get an unbiased second opinion.
As I said in the other thread, I don't know the qualifications of the contactor, engineer or AHJ (inspector); I know mine (and they're pretty good). If not corrected now, "AHJ approval" won't protect your employer from liability should an accident occur. Actually, an accident isn't necessary - an employee complaint is all that's needed and correcting the issue will then be totally on your employer.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
As I said in the other thread, I don't know the qualifications of the contactor, engineer or AHJ (inspector); I know mine (and they're pretty good). If not corrected now, "AHJ approval" won't protect your employer from liability should an accident occur. Actually, an accident isn't necessary - an employee complaint is all that's needed and correcting the issue will then be totally on your employer.

Not in and of itself a "necessary and sufficient condition". Depending on the size of the jurisdiction, you might find the code official is also the electrical sub code official and the electrical inspector. If so, and he/she is already on board with this choice, the complaint will go nowhere. It's unlikely anyone on the political side in the jurisdiction will butt heads with the Building Department on something like this.
 
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