Industrial Lighting Daisy Chain

[Todd-Eco]

I'm trying to understand the NEC codes related to daisy chain wiring of industrial spaces (warehouses, manufacturing plants, etc). It is my understanding that the maximum allowable rubber cord whip on a fixture is 6' long. Anything longer than this would have to be MC cable (with no restriction on length).
Many companies that I meet with are converting from fluorescent fixtures mounted end to end and going to LED fixtures. The older fluorescent fixtures (end to end) use the fixture as conduit. Many of the new linear LED fixtures cannot be used as conduit, so one of two options come about (Running conduit along side the lights and junction boxes between each light or utilizing diasy chain wiring between the fixtures. I've seen a mixture of items on the market and when I speak to various electricians there seems to be confusion on what is allowable by code.
If you want to mount 4' long linear LED fixtures on 8' centers, you end up with a gap of 4' between the lights. I've seen daisy chain cords offered by some companies. At 110V or 277V what is the code requirement for the allowable daisy chain cord length and wiring to be used. The fixtures I am looking at typically range from 50 to 110 watts each. Can you use UL rated rubber cord between fixtures (if cord is under 6')? Is MC cable required for cords longer than 6'? Are there any other items we should look out for in these types of projects? Thanks for your help.

 

[jumper]

Pretty sure you cannot use cord to daisy chain the light fixtures. Cord seems to only be allowed for connection to an individual fixture.

(C) Electric-Discharge and LED Luminaires.
(1) Cord-Connected Installation. A luminaire or a listed
assembly shall be permitted to be cord connected if the
following conditions apply:
(1) The luminaire is located directly below the outlet or
busway.
(2) The flexible cord meets all the following:
a. Is visible for its entire length outside the luminaire
b. Is not subject to strain or physical damage
c. Is terminated in a grounding-type attachment plug
cap or busway plug, or is a part of a listed assembly
incorporating a manufactured wiring system connector
in accordance with 604.6(C), or has a luminaire
assembly with a strain relief and canopy having
a maximum 152 mm (6 in.) long section of
raceway for attachment to an outlet box above a
suspended ceiling

 

[Todd-Eco]

Thanks for your help. It appears that a fair amount of major manufacturers are offering daisy chain cords (linkable lights seems to be the phrase). I only see them in short cord lengths (13" to 18") and typically for 110V. There must be a code that applies to the length and voltage.
http://www.acuitybrandslighting.com/library/ll/documents/specsheets/ucld.pdf - 13" Cords
http://www.homedepot.com/p/Lithonia...ite-LED-Strip-Light-MNLK-L48-830-M4/205570117 - 18" cords

 

[Strathead]

Thanks for your help. It appears that a fair amount of major manufacturers are offering daisy chain cords (linkable lights seems to be the phrase). I only see them in short cord lengths (13" to 18") and typically for 110V. There must be a code that applies to the length and voltage.
http://www.acuitybrandslighting.com/library/ll/documents/specsheets/ucld.pdf - 13" Cords
http://www.homedepot.com/p/Lithonia...ite-LED-Strip-Light-MNLK-L48-830-M4/205570117 - 18" cords

Honestly, I just wouldn't worry about it. If it is listed then they are OK. It could be that the connection is a cable, not a cord for code purposes, or whatever.

 

[Todd-Eco]

I should have prefaced my original post a bit more. I'm currently working with a British manufacturing that is launching a series of industrial LED lights in the US. My team as been asked to investigate cord length, as they are hoping to offer linkable daisy chain cords for 110V and 277V at 6' and under.

 

[augie47]

You seem to be in somewhat of a "Catch 22" situation between NEC 400.8, 410.61, possibly Art 604 vs the manufactures listing.
On the front end, such an install appears to be a NEC violation but if the "assembly" (including a cord) is listed it would likely meet local approval but I can see some interesting discussions with inspectors.

 

[Smart $]

Hmmm.... just not seeing cord-type daisy-chain lighting fixture system at the industrial plants in which I have worked. But then again, I tend to think on the heavier side of industrial, e.g. steel mills, power plants vs. small parts manufacturers.

 

[mgookin]

I should have prefaced my original post a bit more. I'm currently working with a British manufacturing that is launching a series of industrial LED lights in the US. My team as been asked to investigate cord length, as they are hoping to offer linkable daisy chain cords for 110V and 277V at 6' and under.

Since all luminaires are required to be NRTL listed, I'm going to suggest you discuss this with whatever testing laboratory is going to be doing your listing.