daisy chaining fluorescent 4' ceiling fixtures?

[Piper]

I don't know if there is a standard acceptable code answer to this, regional or otherwise, but I'm in Ontario Canada FWIW.

I have 3 rows of 9-4' long fixtures that I want to install on my new garage ceiling. I want to have the fixtures come on so that either 3, 6 or 9 of the fixtures in each row will turn on with 3 separate switches. (ie: you get 1/3, 2/3 or all of the fixtures on depending upon how many switches you turn on). I don't know what code suggests regarding the wiring of this. I'd love to be able to just run the wires thru the fixtures with 3 boxes on 1 end (as the fixtures will **** together) but my hunch is that while this would work it would be against code.

How is this done as suggested by code?

Piper

 

[tfi racing]

No problem,mount them end to end.There likely is a sticker inside that says "suitable for continuous row mounting",the fixtures are allowed to be used as raceways for the lighting circuits ONLY and is common practice.You will need a bushing at each knockout to protect the conductors(RW90 or THHN),bolt them together or run a ground to assure bonding continuity(some inspectors want both).What kind of fixture are they?Some are designed to have the end plates removed for row mounting,some just have 1/2" knockouts,the real cheap ones you have to drill yourself.

 

[Piper]

ya, they have 1/2" knockouts. I was concerned about the using the fixture as a raceway. I'll check with an electrician friend but doing as you've suggested will make the install way easier.

 

[Aceman]

Some electricians might not think so but the way I read 410.65 in the NEC, it's allowed. Canada, might feel differently though....

 

[Charles (in GA)]

In the US, under the NEC, I think that 410.32 would be the governing section. (2008 code)

Wiring Supplying Luminaires (Fixtures) Connected Together. Luminaires (fixtures) designed for end-to-end connection to form a continuous assembly, or luminaries (fixtures) connected together by recognized wiring methods, shall be permitted to contain the conductors of a 2-wire branch circuit, or one multiwire branch circuit, supplying the connected luminaires (fixtures) and need not be listed as a raceway. One additional 2-wire branch circuit separately supplying one or more of the connected luminaires (fixtures) shall also be permitted.

What this says is that, under the NEC, the max is two circuits can be run in any one fixture, the one that feeds it, and one other circuit. It does not allow for a total of three circuits, except by using a multi-wire circuit plus a single branch circuit. Don't know what Canada would allow. Note the spelling of Luminaires is as the NEC spells it, not as Webster's does (Luminaries).

Charles

 

[tfi racing]

Wish I had access to an online CEC that I could cut and paste!
CEC 30-312(1) is similar in wording to NEC 410.32.Actually Charles,in a three phase situation your rule could be interpreted as allowing four branch circuits in a row of luminares(why they use a silly french word,I don't know, its in both the CEC and NEC!),the Canadian rule doesn't allow the fourth branch circuit.
But back to our OP,he is likely not running multiple branch circuits in a row of lighting,just three switch legs,he could likely switch all nine individually if he really wanted to and still meet the code,at least on this side of the border.

 

[Charles (in GA)]

Wish I had access to an online CEC that I could cut and paste!

NEC's online version is a flip the page book, that cannot be copied. It is locked tight so there is no way to cut and paste. I hand typed the paragraph from my printed code book.

CEC 30-312(1) is similar in wording to NEC 410.32.Actually Charles,in a three phase situation your rule could be interpreted as allowing four branch circuits in a row of luminares(why they use a silly french word,I don't know, its in both the CEC and NEC!),the Canadian rule doesn't allow the fourth branch circuit.
But back to our OP,he is likely not running multiple branch circuits in a row of lighting,just three switch legs,he could likely switch all nine individually if he really wanted to and still meet the code,at least on this side of the border.

Not sure of the amp draw, but with 27 fixtures, I'm sure he will have to use at least two circuits, most likely easiest thing to do is use three, one for each switch.

Charles

 

[nadogail]

FWIW in California, being able to turn on or off the lights in portions is a requirement in any room with natural light available. Energy Conservation Codes. This enables a less than full power use of energy. Natural light harvesting is what it is called.

All this and two dollars will get you a cup of coffe in a cheap restaurant

 

[nissan_crawler]

FWIW in California, being able to turn on or off the lights in portions is a requirement in any room with natural light available. Energy Conservation Codes. This enables a less than full power use of energy. Natural light harvesting is what it is called.

All this and two dollars will get you a cup of coffe in a cheap restaurant

I'm reminded more and more why I'm glad I don't live in that state lately. Controlling light use in somebody's home? Good grief.

 

[nadogail]

It is not control of the use of lights. It is making it possible to avoid an "All or Nothing" situation.

 

[Torque1st]

Not sure of the amp draw, but with 27 fixtures, I'm sure he will have to use at least two circuits, most likely easiest thing to do is use three, one for each switch.

Charles

I would run one branch circuit for each row. Put the emergency light on the middle row breaker, or multiple E-lights. Run 90°C wire (THHN etc), 3 hots to each row of fixtures with one neutral and one ground just to make sure everything is bonded well.