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Flourescent light just stops working ...

Ginni6's picture

First, we (my husband and I) are NOT electricians but have as homeowners (& one time ownerbuilders) taken on a few little electrical things, like, old light switches, installing under cabinet lights, etc. We’re now renting and have put up a couple of fluorescent lights, in a series, and connected to the overhead light in a main floor work room.

We then decided to put a single fluorescent fixture (the exact same brand as used upstairs) in a downstairs office. We’re now on the 4th unit! Each time we install the fixture, about 1-2 weeks later it just stops working one morning. We’ve tested the bulbs from the non-working unit in the fully working, upstairs unit and they are fine. We, and the electrical store where we purchased the fixtures from, concluded with the first 2 units that the ballasts must have been defective! (hum-m-m … thinking maybe not, now.) We’ve tested the outlet that the light plugs into and the grounds are reading ‘correct’ using a little meter. And, there is other equipment on the same outlet as the fluorescent fixture that is working and has always worked fine through this whole ordeal. Thinking we may have run into some metal, like ductwork, when screwing the unit into the ceiling, we tested the screws that hold the unit into the ceiling and they are reading .5 without the unit plugged in and 1.5 with the unit plugged in. We’ve used a volt sensor gadget over the ceiling and walls and get readings beeping in places we wouldn’t expect, like, spans of 1-2 feet and then no reading within an inch in a full 360 degree ‘around’ the outlet! And, there are no other electrical problems in the room. - - I’d appreciate any ideas to get the next fluorescent unit to work … and finally be done with this. Let me know what more information you may need. Thank you so much. Ginni

(post #115837, reply #1 of 11)

Does the fixture trap heat? Most CF bulbs don't like to run hot.


(post #115837, reply #2 of 11)

Hi Scott,

No, the bulbs are open - no covering. Also, the unit is a 'American Fluorescent' commercial grade fixture with 2 of the skinny kinds of bulbs. And, the room is kept rather cool because of computer equipment.


(post #115837, reply #3 of 11)

Hi Scott,

I just realized I wasn't clear on 'what kind' of a fluorescent fixture this is. It's a 4' strip light with 2-4 foot long, 32watt bulbs. It's the kind used in garages and workshops.


(post #115837, reply #4 of 11)


If you're into experimentation.

Swap out the ballast from one of the upstairs fixtures (same as one down you say?).


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


(post #115837, reply #7 of 11)

Hi Calvin,

I usually am the first to go for it and test it all out. But I'll need to bend some metal to get the ballasts out and then cut and re-wire, all of which may may mean I can't exchange the 'not working' unit. I'll certainly suggest we do a quick change out at the counter when I return it, though.

By the way, the two fixtures upstairs have never failed and they are the exact same make and model.

Thanks for your suggestion.


(post #115837, reply #5 of 11)


The detective work you've done is admirable, and having three fixtures fail is pretty frustrating! 

As far as the testing you've done, the best test for this kind of sutuation is the little plug-in polarity tester, with three lights.  All that matters is that there's power at the receptacle and the equipment ground is good.  The fact that the fixtures worked for a good while suggests that it's the fixture. 

The fact that three fixtures failed in pretty much the same pattern suggests a couple of possibilities:

1. Failed ballast, factory defect.  The fixture manufacturer may have gotten a load of bad ballasts, and all of the fixtures you got had them.  You might try calling the fixture mfgr directly, and see what they have to say.   

I'd expect the "electrical store" where you bought 'em to have made a warrantee claim against the manufacturer, and the manufacturer to have acted quickly (with a recall) if the ballasts were defective.  Because the fixture is cord-and-plug connected, it's considerd a consumer product.  You might check the Federal Consumer Products Safety Commission recall info page, to see if the fixture is on a recall list.

2. Failed ballast, because of a problem with the wiring in the fixture, or installation of the wrong lamps (aka tubes).  The second possibility is more likely; if the fixture was wired wrong during manufacture, it'd likely not work correctly, right out of the box.

So, are you using the right lamps?  Good quality new fixtures typically use T8 lamps, but there are a variety of lamps and many have a bi-pin base and fit in the same socket.  The box the fixture came in and the info/installation sheet for the fixture tell you what lamp the fixture requires.  For instance, using a T12 lamp in a T8 fixture will ruin the ballast in short order.

So, I suggest you buy and try a different fixture and see what happens.

Good luck,


p.s. Suggest you fill out your profile!

(post #115837, reply #6 of 11)

I agree with the previous post.  A possible cause would be using the wrong size lamps.  Be sure you are using T5, T8, or T12, whichever is correct for your fixture.  Usually there is a sticker on the housing, if not, the ballast would definitely be marked.  Also check the ballast to see if it is rated for house current 110 to 120 volts.  If you have a ballast for a different voltage used in commercial buildings (240, 277, or whatever) it won't work right in a home.

Some fixtures are not rated for fastening flush to the ceiling.  They overheat.  Make sure yours can be flush mounted if that's how you have it mounted.

(post #115837, reply #8 of 11)

Hi Cliff & WayneL5,

I agree that all this seems now to point to faulty fixtures. All FOUR of them!!

As you suggested, Cliff, I just did a search for recalls on the pro-TRONIC II, Flourescent Lamp Electronic Ballast made for American Fluorescent but found nothing. I will return the fixture to the electrical store and then ask them as well if there is a recall. And, if not, maybe there should be! And, I will ask that they contact the company directly since they should have the number more handy than I would.

I am corrected in using the term ‘tubes’ or ‘lamps’ instead of bulbs. And, I have been using the correct tubes/lamps – T8.

WayneL5, the fixture is rated for flush mount and I just took their word that an ‘in the home use’ would be okay as opposed to a commercial building application. I will, however, go ahead and make a mention of that for a comment when I return this fixture.

Finally, I will take your suggestion to try a different fixture, Cliff. I guess we just lucked-out with the first two fixtures still working upstairs! So now we’ve installed this same fixture six times, all total !!

I appreciate all the responses and suggestions. And, if anything else comes to mind please just drop a line in the next few days.


PS: profile is undated

(post #115837, reply #9 of 11)

Is it an electronic or magnetic ballast? It sounds like it's failing to start correctly.

IIRC you can test the starter by checking for max voltage across the lamp while you turn it on. It should be a quick jolt of a few hundred volts.

The amount of metal around it may affect the startup, but it's usually when there's not enough metal (inductance) to help the arc get started. Too much inductance might affect the current, but I think it would dim it rather than stop it. That might affect an electronic ballast.

(post #115837, reply #10 of 11)

Hi KHWillets,

The fixture has an electronic ballast.

"It sounds like it's failing to start correctly."
Each of the 4 fixtures started up and worked fine for 1-2 weeks before just failing to come on one morning. I would think we would have heard or seen something on 'startup' that would have indicated something was not right. You think? Each one just didn't light up one morning. - Not sure this really addresses what you offered though.

By now we're just really tired of all the putting up and taking down the same light so we're just going to return this last one for a different brand. Entirely too much time has been spent on getting this one light fixture in this room!!

Thanks for your thoughts on this.


(post #115837, reply #11 of 11)


Another thought: is the failing downstairs fixture controlled by a dimmer switch?  It takes a special ballast for that.

Oh, and one last thought (a la Columbo)--any chance the downstairs fixture is GFI-protected?  Each fixture worked for a couple of weeks, then completely stopped.

If you tested for power at the receptacle immediately after the fixture stopped working, befire any GFI was found tripped and was re-set, this could be ruled out.

But is there any chance the power for this light is downstream and protected by a GFCI receptacle or breaker which occasionally trips, and is re-set but considered unrelated to the fixture? 

If this is the case, the fixture would stop working, along with the other segments of the circuit, which may not be noticed, and the GFI re-set, but the fixture removed by then and the GFI trip not linked to the light stopping working. 

Yes, a long shot, I know.  You wouldn't expect a lighting segment of a circuit to be GFI-protected, but if a GFI receptacle was either wired unusually or was replaced by someone who lost track of the wiring set-up, the downstream part of the circuit might be protected.