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emt and lfmc

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sparkmantoo

Member
Location
Virginia
can i run emt and install a piece of lfmc in the run and not have to pull a ground wire? the size of the run is 2" and the lfmc is +/- 18" long. i have to install the lfmc to get from one elevation to another.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: emt and lfmc

You need an EGC in the raceway or a bonding jumper around the LFMC. See 250.118(7). 2" LFMC is not an EGC.
Don
 

sparkmantoo

Member
Location
Virginia
Re: emt and lfmc

my fittings are listed for grounding, it is not for a flex connection, doesn't exceed 6 feet, and is not listed in the ones that have a minimum ocp. so why can't i use it as a egc. imo i have met the requirements. it does not say that i can't use it.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: emt and lfmc

sparkmantoo,
Your LFMC does not meet all of the requirements in 250.118(7). It is larger than 1.25" and per the code is not suitable for use as an EGC.
Also look at the following from the UL Guide Information for "Flexible Metal Conduit, Liquidtight".
Liquid-tight Flexible Metal Conduit
The following are not considered to be suitable as a grounding means:
1) The 1-1/2 in. and larger trade sizes.

2) The 3/8 and 1/2 in. trade sizes where used on circuits rated higher than 20 amps, or where the total length in the ground return path is greater than 6 ft.
3) The 3/4, 1, and 1-1/4 in. trade sizes where used on circuits rated higher than 60 amps, or where the total length in the ground return path is greater than 6 ft.
A question. Is the flex supported within 12" of each of the terminations?
Don

[ October 30, 2003, 06:56 PM: Message edited by: don_resqcapt19 ]
 

sparkmantoo

Member
Location
Virginia
Re: emt and lfmc

okay that makes sense now. i don't keep a copy of the ul guidlines handy so that is some valuable info. however the code does not say that it is not suitable as a ground and if it is meant to be implied then it should be noted in the code in section 351-4(b)(NEC 1999)" uses not permitted " and 351-9 "grounding". somewhere it should read " 11/2in lfmc or larger shall not be used as an equipment ground ". gray area to me. i was going to install a jumper anyway just because i feel better knowing that there is a suitable bond around that flex. the situation arose becuase of the tight area that we were working in and there was not sufficient room to bend a piece of 2" conduit and install it correctly. and yes my flex is supported and secured.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: emt and lfmc

250.118(7) says that only sizes 1.25" and smaller are suitable for use as an equipment grounding conductor, and with limitations.
Don
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Re: emt and lfmc

sparkmantoo: if you'll look at the jacket of the 1 1'4" LTFMC it will state a separate equipment grounding conductor is required. It can be inside, or if outside it can't exceed 6 feet. On 1 1/4" it states separate EQC required on circuits over 60A> I seldom install 2" LTFMC but the jacket may have the EGC information on it. By the way this information is in the UL white book which is now avaiable on line
 

sparkmantoo

Member
Location
Virginia
Re: emt and lfmc

so can i run a bonding jumper from the emt outside the liquidtight and terminate it to the my connection box? the flex is only 18 inches or so and how do i do this?
 

pierre

Senior Member
Re: emt and lfmc

The answer for this is in the listing, it is not too clear in the NEC.
The UL White Book lists it under DXAS and it states; " The following are not considered to be suitable as a grounding means:
1) The 1-1/2 in. and larger trade sizes. "

IMO that statement should be added to the NEC.
But... this proves the statement I make at all of my NEC code seminars.

" It is impossible to work everyday in this field without the UL White Book as well as the NEC".

Pierre
 
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