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connection to lay in fixtures #212863
02/22/14 04:22 PM
02/22/14 04:22 PM
S
sparkync  Offline OP
Member
Joined: Oct 2002
Posts: 830
NC
It's my understanding that in trade sizes of 3/8" flex whether a/c cable etc. etc., that the flex cannot be over 6ft. in length when connecting to lay in light fixtues. Is there any exceptions to this anywhere? I'm seeing lengths greater than this on jobs. Thanks again

2017 / 2014 NEC & Related Books and Study Guides
Re: connection to lay in fixtures [Re: sparkync] #212864
02/23/14 10:43 AM
02/23/14 10:43 AM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 951
Chicago Illinois USA
That can be found in the Article on that particular wiring method (FMT, FNMT, etc.) in the section headed 'uses not permitted'.


Ghost307
Re: connection to lay in fixtures [Re: sparkync] #212865
02/23/14 11:55 AM
02/23/14 11:55 AM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,274
Fullerton, CA USA
MC cable is allowed to be unsupported for 6' under these circumstances.

330.30(D)
(2) Is not more than 1.8 m (6 ft) in length from the last
point of cable support to the point of connection to
luminaires or other electrical equipment and the cable
and point of connection are within an accessible ceiling.
For the purpose of this section, Type MC cable
fittings shall be permitted as a means of cable support.

The same thing applies to AC cable. 320.30(D)(3).

Flex has such a rule, too. 348.30(A), Exception #4

There is no limit as to the length of supported cable or flex.


Re: connection to lay in fixtures [Re: sparkync] #212866
02/23/14 08:14 PM
02/23/14 08:14 PM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 951
Chicago Illinois USA
348.20 (A)(2) limits some smaller sizes of FMC to 6' lengths.
356.12 (3) limits LFNC to 6' lengths.
360.12 (6) limits FMT to 6' lengths.
You should always check for local amendments that may have additional allowances or restrictions.

Also watch out for the 6' length limitation in 250.118 (5) if you're not running a separate grounding conductor through the flex. This is the result of UL only testing 6' lengths for their suitability as a grounding path.


Ghost307
Re: connection to lay in fixtures [Re: sparkync] #212867
02/23/14 09:00 PM
02/23/14 09:00 PM
T
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Listed lighting whips -- 6' -- with black, red, white and green are availabel -- by the drum.

They look, from a distance, just like MC, after installation. They use trick flex-connectors -- straights only -- that mate with 3/8" flex. This is a trade size NOT distributed to our trade -- just to NEMA players -- so they can make these whips and sell them to us.

They are restricted to feeding just one (1) lumiere, of which a master-slave combo is deemed one fixture.

Being factory dimensioned to 6' they are easy to inspect. They are easy to make up in the lumiere -- since their conductors are sized, just so. Orange wire nuts are favored -- even Blue (tiny) wire nuts can fit. (I just think of them as slower, touchier.)

You still have a tiny conductor going under a wire nut sized for #12 -- unless you're using the trick Wago. This gadget is sized for a single lumiere tap along with #12 conductors. (IIRC it can take #18 through #16)

These dinky tap conductors are specially exempted by the lumiere tap rules.

This product is NOT normally used by small electrical contractors since the job has to be of scale before its economics turn favorable. The dinky conductors are a snap to install inside the limited space found in most lay-ins and most hat fixtures. That's not a trivial advantage when the job scales up.

Wagos are tough to beat for lightly loaded lighting circuits. They're now popping up in all of the factory prepped assemblies -- now advertized in EC Magazine with each issue.

Our trade is designing out field labor. The bigger the job, the more it happens.


Last edited by Tesla; 02/23/14 09:05 PM.

Tesla
Re: connection to lay in fixtures [Re: sparkync] #212869
02/23/14 10:55 PM
02/23/14 10:55 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,287
Estero,Fl,usa
I usually saw a guy with a roll of MC, they made up the whips on the floor and hung them up to the boxes that were already there or to the luminaire next to it. If support was an issue with the whip, they clipped it to an "electrical" support wire or two.


Greg Fretwell
Re: connection to lay in fixtures [Re: sparkync] #212871
02/24/14 10:20 PM
02/24/14 10:20 PM
S
sparkync  Offline OP
Member
Joined: Oct 2002
Posts: 830
NC
Just to double check then, (in a lay in ceiling space), I can run as much M/C cable as I like as long as it's supported correctly with the approved connectors? thanks again..

Re: connection to lay in fixtures [Re: sparkync] #212876
02/25/14 07:09 AM
02/25/14 07:09 AM
T
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
MC is the default favorite from coast to coast.


Tesla
Re: connection to lay in fixtures [Re: sparkync] #212877
02/25/14 11:11 AM
02/25/14 11:11 AM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,274
Fullerton, CA USA
Originally Posted by sparkync
Just to double check then, (in a lay in ceiling space), I can run as much M/C cable as I like as long as it's supported correctly with the approved connectors? thanks again..


Yes, you can with approved supports (Caddies, one holes, ty-wraps, etc)




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