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Old 05-02-2013, 08:06 PM   #1
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Installing fluorescent light fixtures


I picked up four 4-lamp fluorescent light fixtures off of Craigslist. They were pulled from an office building's drop ceiling during a remodel. They look like this:



I want to remove the current two 2-lamp fixtures in my drywall ceiling garage and replace them with two of the new ones and run wire to two new places. I have a few questions on the best install method for these guys. Two of them have 277V ballasts in them that I will be replacing with 120V.

1) What type of cable and connectors should I use? From above the ceiling, the current fixtures look to have a sort of thick SO cable going from the light switch to the first fixture's box (it has a box much like a fan), and then from there to the second fixture's box. The fixtures are then mounted flat against the drywall. The new fixtures have what looks like rectangular cutout replaced with a metal plate that an MC cable was attached to. Can I just mount the fixture such that the rectangular cut out is over the existing box so the wire just comes in and connects to the ballast? What about grounding? Then I would just install two new boxes for the other two fixtures. Can I just run NM cable from the 2nd fixture on to the third, and then fourth? I am not sure why a thick SO cable was used here... perhaps because they are right near the attic entry way and they feared people placing boxes on them. The new two fixtures would be farther out.

2) The ceiling joists will be running perpendicular to how I'd like to mount the lights. Can I drill holes in the fixture to screw through it and into the ceiling joists? I should be able to screw into three, maybe four joists. The current fixtures use a sort of toggle bolt through the drywall to hold them in place.

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Last edited by BrandonD; 05-02-2013 at 08:10 PM.
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Old 05-03-2013, 11:19 AM   #2
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Installing fluorescent light fixtures


The fixtures are designed to be "laid" into a drop ceiling. Hence the term "drop in" or "lay in".

Mount the fixtures to the structure with sufficient fasteners and wire with any method you like. Yes, you can make holes in the fixture for mounting and to install connectors.

Romex (NM) and proper connectors.
EMT conduit.

Pick and do a neat compliant job.

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Old 05-03-2013, 03:43 PM   #3
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Installing fluorescent light fixtures


Thanks for the info. I'm aware their intended purpose is in a drop ceiling but I couldn't pass the deal up. My hobby requires good lighting and to get four new 4-lamp T8 fixtures I'd be looking at at least $200. As of now I'm looking at only $65 for the cost of the fixtures and two new 120V ballasts. Plus they even came with the lamps

I just wanted to be sure that they would be fine mounting through the bottom of the fixture through the drywall ceiling and into the ceiling joists. They seem well constructed.

Do I not have to worry about grounding? Can I just use a plastic ceiling box for the romex to enter?

Also, to confirm, the circuit is on a 20A breaker. I have to use 12AWG wire even though 14AWG would be sufficient for the fixture?
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Old 05-03-2013, 04:56 PM   #4
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Installing fluorescent light fixtures


They have knockouts on the ends (and probably the back) for your romex to enter the fixture. Just use the appropriate sized strain relief (romex clamp).

They should have a grounding point inside the fixture. Many fluorescent fixtures do not work well without a ground.

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Old 05-03-2013, 05:05 PM   #5
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Installing fluorescent light fixtures


The problem with using the knockouts on the side of the fixture is the romex would be exposed coming out of the ceiling and into the knockout. I'd prefer a cleaner install if possible by going through the bottom of the fixture. They all have these plate inserts (pictured below). Could I just cut a rectangle out of the drywall where this plate will be and then attach the romex to the hole with a clamp? So not even use a box?

[Edit] I guess I will at least need a box for three of the four to house the wire nut connection going to the next fixture?


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Old 05-03-2013, 06:37 PM   #6
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Installing fluorescent light fixtures


You do not need a box for those fixtures. The splices will be contained in the pan that covers the ballast.
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Old 05-03-2013, 09:03 PM   #7
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Originally Posted by BrandonD View Post
As of now I'm looking at only $65 for the cost of the fixtures and two new 120V ballasts. Plus they even came with the lamps
I'm not sure, but I think the only new ballasts you can get now are the electronic ones, and those don't run the old tubes that were powered by the old type ballasts, if I'm right on the availability, those old tubes are junk along with the old ballasts, so you'll be buying all new tubes then too.

The new tubes are brighter and use less power, but I've had to replace several of the electronic ballasts due to failures- made in China like everything else is these days.

I know when I replaced about 100 balasts at work several years ago, the electrician I worked helping run wires in the new addition said the old rapid start type ballasts and tubes were going away and it was all going to the electronic balasts, and that they take different tubes (they are also slimmer in diameter) that are not interchangable.

Whether or not the change is complete yet, or what's still sitting in warehouses of the old stuff that can still be bought I don't know, but that's what he told me- going the way of the incandescent light bulb.

If I read it right, the fixtures were on 277 volts? it would seem the tubes those ballasts were running would not work on a 120volt replacement ballast anyway?

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Old 05-03-2013, 09:44 PM   #8
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You do not need a box for those fixtures. The splices will be contained in the pan that covers the ballast.
Great. So my plan is to replace the existing two fixtures with two of the new ones, centering the rectangular cutout over the existing ceiling boxes. The romex from the switch will come in and the romex going to the 2nd fixture will go out the same hole as it is now. For the second fixture I will have the incoming romex come in the existing ceiling box and then cut a new hole for the new romex to go from the 2nd fixture to the third. Then I will install the two other fixtures, with the 3rd having the incoming romex coming in one rectangular insert and the outgoing romex to the final fixture will go out a second insert. The final fixture will simply have one rectangular insert for the incoming romex.

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I'm not sure, but I think the only new ballasts you can get now are the electronic ones, and those don't run the old tubes that were powered by the old type ballasts, if I'm right on the availability, those old tubes are junk along with the old ballasts, so you'll be buying all new tubes then too.

The new tubes are brighter and use less power, but I've had to replace several of the electronic ballasts due to failures- made in China like everything else is these days.

I know when I replaced about 100 balasts at work several years ago, the electrician I worked helping run wires in the new addition said the old rapid start type ballasts and tubes were going away and it was all going to the electronic balasts, and that they take different tubes (they are also slimmer in diameter) that are not interchangable.

Whether or not the change is complete yet, or what's still sitting in warehouses of the old stuff that can still be bought I don't know, but that's what he told me- going the way of the incandescent light bulb.

If I read it right, the fixtures were on 277 volts? it would seem the tubes those ballasts were running would not work on a 120volt replacement ballast anyway?
Not sure about the 277V tubes not working on new 120V ballasts. I can buy new tubes if needed, no biggie

Two of the four fixtures are wired with 120V ballasts so I don't have to change anything with them.
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Old 05-03-2013, 10:05 PM   #9
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....Not sure about the 277V tubes not working on new 120V ballasts. I can buy new tubes if needed, no biggie

Two of the four fixtures are wired with 120V ballasts so I don't have to change anything with them.
There is no such thing as "277 Volt tubes"

It's the BALLAST that changes the input voltage to the proper operating value for the tubes to work. Many ballasts these days are rated as "multi-volt" meaning that they will operate on any input voltage from 120 through 277. If that is the case, you won't have to change anything.

But if they are rated at 277 only, then you will have to change `em.

The same bulbs can be used on either one.
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Old 05-04-2013, 01:37 AM   #10
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But if they are rated at 277 only, then you will have to change `em.
The OP is in Florida so it's not some foreign country, so what's that odd 277 volt anyway? I never heard of a 277 volt fluorescent light fixture.
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Old 05-04-2013, 05:05 AM   #11
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The OP is in Florida so it's not some foreign country, so what's that odd 277 volt anyway? I never heard of a 277 volt fluorescent light fixture.
277 Volts is not available in a dwelling. In the US, it's quite common in many commercial and industrial settings, however. The nominal system voltage is 277/480 Volts 3 phase.

In Canada, you're more likely to find 380/600 Volts in industrial applications.
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Old 05-04-2013, 04:31 PM   #12
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277 Volts is not available in a dwelling. In the US, it's quite common in many commercial and industrial settings, however. The nominal system voltage is 277/480 Volts 3 phase.

In Canada, you're more likely to find 380/600 Volts in industrial applications.
Odd, I've never seen or heard of that voltage before now, but then what Im most familiar with- New York City is powered by one company Consolidated Edison and the power they put out is only what is available there, so you get the normal single and 3 phase voltages for that city 120v, 220 or 240 I seem to remember, but the subway system produces or I should say converts (or did) AC for their own DC power, 600 volts.

I guess if you go to a different large city like Chicago or Detroit you find more specialty voltages for large factories and industrial plants which NYC does not have (such as the massive auto makers plants)
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Old 05-04-2013, 05:07 PM   #13
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277 volts is a single leg from a 480 circuit and a neutral.
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Old 05-04-2013, 06:03 PM   #14
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There is no such thing as "277 Volt tubes"

It's the BALLAST that changes the input voltage to the proper operating value for the tubes to work. Many ballasts these days are rated as "multi-volt" meaning that they will operate on any input voltage from 120 through 277. If that is the case, you won't have to change anything.

But if they are rated at 277 only, then you will have to change `em.

The same bulbs can be used on either one.
I had hoped that the guy was mistaken when he said they were 277V ballasts or that they could be wired on 120V after reading up on them. I figured it was a good deal even if I had to replace all of the ballasts. Lucked out when I found two to be 120V but the other two read 277V only.

I am hoping to get these up tomorrow. I will let you guys know how I did.
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Old 05-04-2013, 06:21 PM   #15
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I had hoped that the guy was mistaken when he said they were 277V ballasts or that they could be wired on 120V after reading up on them. I figured it was a good deal even if I had to replace all of the ballasts. Lucked out when I found two to be 120V but the other two read 277V only.
Yeah but the thing is, the ballasts are often the most expensive part of the whole fixture, they run usually about $15-$20 and up each. I saw some ballats priced $53 each, I don't know what differences there are between them, or why one T8 ballast is $16.99 and another is $53.00 but it would suck having to replace two $53 ballasts in every lamp!

There are 277 volt units, they appear they might be able to be wired for 120 volts per:

Sylvania 49908 4 Lamp 120V/277V Ballast for 32W T8 Fluorescent Light Bulb (S5210)

http://www.amazon.com/Sylvania-49908-Ballast-Fluorescent-S5210/dp/B002CYVGX2


Those are basically $17 each plus shipping, but I've seen other ballasts priced around $29 and $39 each, so it all depends on which ballast you need and the quality desired, but if a new fixture with bulbs was $100 and replacing 2 ballasts in a used one ran $29 each plus having to replace the bulbs to run from different ballasts, and figuring the used purchase price added in too, it doesn't become a very good deal by then at all.


Hopefully you can use these as they are just wired differently.

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