Introduction: Fluorescent Shop Light Repair

Picture of Fluorescent Shop Light Repair

Fluorescent lights from places like Home Depot look good and seem like a real bargain but the ballasts inside don't last. The lights come with a warranty but removing the light and returning it about once a year isn't worth the trouble.
I have several lights in my garage and basement from Home Depot that I installed about 3 years ago. Although I have never had to replace the tubes in them yet all of the ballasts have gone bad in that time.
This instructable will show you how to repair and upgrade cheap fluorescent lights so they will be better than new and will last a long time.

Step 1: Materials Needed

Picture of Materials Needed

The materials you need are
The new ballast. I have chosen is Advance REL -2P32-SC because I found it cheap on ebay. I am using 2 32watt T8 tubes per fixture. This particular ballast is discontinued, but Advance sells newer type ballasts such as ICN-2P32-N that install the same way.
the main things to look for are voltage (probably 120 volt if this is in your home), number of tubes the ballast will light (probably 2), the type of tubes you will be using (probably T8. I prefer to use T8 because they are more efficient than T12 and T8 will start in cold weather) and the wattage of the tubes you will be using (probably 32 watt)
Small wire nuts.
a pointed sheet metal screw
1/4" Nut driver
Wire stripper

Step 2: This Is a Common Problem

Picture of This Is a Common Problem

These ballasts burn out all the time. I got tired of constantly replacing the fixtures, so I decided to replace the ballasts with high quality ones. I have changed more of these ballasts than I can remember, but I have not replaced any of the fluorescent bulbs since I switched to T8.
T8 tubes are more efficient and have a long life.

Step 3: Disassemble the Light Fixture

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First of all unplug the light. Then remove the fluorescent tubes and the shade exposing the ballast and wires.

Step 4: Cut Out the Old Ballast

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Cut all of the wires close to the ballast. The blue disk you can see in this picture is an MOV I installed to try and protect the old ballast. It didn't help, this ballast died anyway. I will remove it as I install the new ballast

Step 5: Install the New Ballast

Picture of Install the New Ballast

Remove the dead ballast and install the new one. The new ballast didn't fit the original mounting hole so I used a pointed sheet metal screw. I didn't need to drill a hole, I just pushed hard as I turned the screw and it worked itself through

Step 6: Connect the Wires

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One end of the light may have a wire joining the two sockets together. This wire is usually yellow. All of the wires on this end will need to be joined together. This instant start ballast doesn't need to heat the filaments in the tubes so only one ballast wire (the red one on this ballast) will need to be connected to all of these wires

Step 7: Connect the Socket Wires

Picture of Connect the Socket Wires

On the other end of the fixture one socket is wired with blue wires and the other socket is wired with red wires. Both red socket wires need to be connected to one of the blue ballast wires, and both blue socket wires need to be connected to the remaining blue ballast wire

Step 8: Finish the Wiring

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Complete the wiring by connecting the black wires together and white wires together. The replacement ballast doesn't use a ground wire, but there should already be a ground wire attached to the fixture housing from the factory. Tuck all the wires up so they are inside the fixture housing so they won't be pinched when you reinstall the shade

Step 9: Install the Shade

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Reinstall the shade, plug in the light and try it out.
The result is you now have a light that is very efficient, it will work in cold weather, the tubes will last a long time and the fixture is dependable.


Orleck (author)2017-07-13

Thanks for the instructable, I've been looking for a way to revive my cheap walmart fixtures, i knew it couldn't be all that hard! :D

DaveK53 (author)2016-05-30

This was interesting, but it did not indicate how to solve my problem. I am installing one fluorescent light, out of eight in our kitchen. Everything went fine until the time came to attach the light to the A/C. None of the wires coming from the other lights matched up. The light I was installing had red, black and green attachments. The wiring tying this light into the chain had brown, blue and green wiring.

en_rov (author)DaveK532016-09-05

I you can't figure this out, you shouldn't be messing with mains woltage in the first place.

RonaldD25 (author)2016-03-27

I can enhance my solar panels by having the arc from my 12,000-volt Jacob's Ladder float up past its face, but now I need to treat the installed panels in lying the horizontal plane. I want to try capturing the arc in a neon or florescent tube. What is likely to happen if I wire 12,000 volts to my neon or florescent tube?

djsliwa (author)2015-11-13

I am having a perplexing problem... I have 4 separate fluorescent light fixtures in my shop. One quit about 6-months ago and I replaced the ballast. Now...quite suddenly...the other 3 have failed. They do not fail all the time - but it appears that if they are left on for a while, they fail (always simultaneously). Do you think it is possible that they are wired in parallel instead of in series?? I've checked and in the failed mode, they do not appear to be powered.

djsliwa (author)djsliwa2015-11-13

Answered my own question.... Checked the original fixture that I replaced the ballast on and found a wire nut that was JUST loose enough to permit the circuit to be broken once the wires got warm. All is normal now.

DaveF17 (author)2015-09-09

Is there a way to take a dual bulb fixture and make it work with one bulb

viesis2000 (author)2013-02-27

Dear technically minded specialists,
There is a problem and I am looking for solution. Maybe You can help me. :)
Description of situation:
Few days ago the electronic Ballast for 15W fluorescent T8 lamp has been burned out. I checked that 2 resistors were broken. Possible reason – during assembling of the unit the solder has got inside and after years has made the short circuit. I am not very qualified electrician and therefore I am looking for help – what exact type of resistors I must get to replace. There are no marks stayed on broken ones. I have other 15W fluorescent T8 lamp with the similar working ballast, but, unfortunately, they are not identical.
There are attached photos of broken scheme and of similar, good one, maybe it help You. My great necessity is to get know – what exact type of resistors I must take to replace.
Being thankful, waiting for response, Very, very sincerely,

MartinL10 (author)viesis20002015-04-18

You have more parts dead, the resistors burned because the npn transistors burned out to short, also the large electrolytic capacitor is bulged so it doesn't work long either. It's easier to buy new than fix this.

mscullin (author)viesis20002014-04-24

The resistors burned out because the ballast failed (they act like fuses). Replacing the resistors will not fix the problem. You need a new ballast.

ReCreate (author)2009-06-18

You should really be carefull when you wire up the cables that go to the Tubes, they can contain up to 5000 Volts!

VadimS (author)ReCreate2012-10-14

I can't remember the voltage (not that high though) but the start voltage is current limited using a capacitor.
Bare 220v lines on the other side of the ballast are fare more dangerous.

Sparkington (author)ReCreate2009-06-19

lol wow no 5000V is a stretch, the only time there could be 5000V is when you switch on and off that only with a wound ballast. 5000V would not be present when using a electronic ballast. If anything for a 240 volt wire wound ballast fluorescent light fitting there would be less than 120volt across the filament of the fluorescent lamp. You would get 5000V in a neon tube display or a TV tube.

ReCreate (author)Sparkington2009-06-19

If anything for a 240 volt wire wound ballast fluorescent light fitting there would be less than 120volt across the filament of the fluorescent lamp.

Its a florescent tube, and it has no filament...

ReCreate (author)pfred22009-06-21

a lightbulb...

pfred2 (author)ReCreate2009-06-21

Indeed. A Fluorescent one at that!

ReCreate (author)pfred22009-06-22

well...they do nothing, all that is needed is that electricity is exposed at the two ends of the tube.

pfred2 (author)ReCreate2009-06-22

Yeah companies just put them in there because they have nothing else better to do. Too bad they never met you huh?

ReCreate (author)pfred22009-06-22

My sarcasm detector went off, Next time use sarcasm tags. Are you being sarcastic?

pfred2 (author)ReCreate2009-06-24

From my point of view you are hardly in the position to tell me what to do. In my opinion your bulb appears to be burnt out!

ReCreate (author)pfred22009-06-24

My Bulb Burnt out? Grr...Cheap Bulbs, Next time I'm getting LED Bulbs.

Sparkington (author)ReCreate2009-06-19

There are filaments in fluorescent lamps they ignite the gas inside the glass tube.

ReCreate (author)Sparkington2009-06-20

XD It has gas inside, but why would you want to ignite it? Its made for making light not for a making bomb, Anyways, it has a gas inside then when electricity is pumped to the ends of the tube it excites the gas, making it glow, light up.

mark49 (author)Sparkington2009-06-19

Filament voltage is only 3.5 V and not used for instant starting

mark49 (author)ReCreate2009-06-19

You are right that there is a fairly high voltage available to start fluorescent tubes. The F32T8 receives about 500V at start up. Although this is a lot less than 5,000 volts it would probably be higher if the high voltage leads weren't connected. Anyway this can still be lethal. Here is a link to an Advance data sheet you might find interesting.

pfred2 (author)mark492009-06-21

I especially like the part where the file states, "PS ballasts precisely heat the lamp cathodes to approximately 700c" Nothing quite like precisely approximating in my book! What I really wanted to know was how many amps were supplied at ignition voltages to gauge the lethality of the device. Being as everyone knows that no one ever died from voltage pressure, but current flow can drop you.

ReCreate (author)mark492009-06-19


richms (author)2009-06-18

Not a fan of instant start ballasts - hell on the tubes with frequent starts compares with ones that preheat - not a big deal when they are on for a long time but if you try to save power you will kill the tubes. I am amazed that T12 is still available - haven't seen one on the shelf in NZ for about 15 years or so other then some specialist tubes. All the cheap fittings here still have a magnetic ballast and a starter which is very annoying...

deteerik (author)richms2011-01-27

The best ballast for frequent on/off aplications is called Program start ballast, they do a sort of preheat and we always install these anywhere we install occupancy sensors or timers.

mark49 (author)richms2009-06-18

I have one light in my garage that has 3 tubes in it, and I have the center tube wired to a photocell so it comes on every night. This one tube has worked for over 4 years every night whether the temperature was 20 below 0 or 90 degrees. Still on the same T8 tube I installed when I modified the fixture from T12 to T8. As far as the T12 tubes, they are still widely available in the USA. They are still the most common size in use, but usually if we are installing several new lights we will make the switch. The problem is that not many ballasts will work on both T8 and T12 so we don't want to mix fixtures and tube types in a large commercial building. This causes chaos when it comes time to re-lamp a large area

Yerboogieman (author)2010-02-19

What about when you plug in a florescent light and have to shake it around for it to shine bright with out flashing a little bit?

bobbyc34 (author)2009-07-30

Thanks so much for the timely instructable! I had planned to replace the Sunpark ballasts found in my lamp fixtures with a direct replacement from Sunpark,(I have 26 florescent fixtures in my garage all purchased from Home Depot on sale and all with a Sunpark ballast). Upon checking prices for replacement ballasts, I found that a direct replacement is $7.00 from Sunpark + shipping. That is more than I paid for the entire fixture!! The Advance ballasts which you used also proved to be too expensive and cost more than just simply replacing the whole fixture with a new one. I shopped around on eBay and was able to get a lot of 10 Sylvania ballasts model QTP2x32T8/UNV ISN-SC for a final price of $4.30 each including shipping! The important thing is that the voltage is correct for your application and that the ballast has the correct number of leads ie for the number of bulbs in your fixture. The Sylvania ballasts which I purchased are not high efficiency, but who cares! They are considerably longer and a tad thicker but fit inside fine. I have installed 4 so far with one more to replace as soon as I can move things out of the way to access. As the author mentioned, the ballasts in these cheap fixtures don't hold up long and I know that over the next short while that I will eventually use up the rest of the bargain ballasts I purchased. Thanks for the excellent instructable!!

pfred2 (author)2009-06-21

The ballasts in my garage have been dying off one by one and I've been replacing them with electronic ballasts. They work better in the colder weather and operate at a higher frequency than the old magnetic ballasts did. One downside for me is they interfere with FM radio reception more than the old ballasts did.

jeff-o (author)2009-06-19

Nice work. I used a few cheap shop lights in my workshop as well and they're holding up fine so far. They've got electronic ballasts though. I modified them from plug-in/pull-string operation to permanent wired, too. If you're not afraid of opening the light fixture, it's a pretty easy hack to bypass the pull string and remove it...

mark49 (author)jeff-o2009-06-19

You're right. I usually do bypass the pull chain switch too because they are unreliable. I have kept the plug in cord though, it makes it easy to disconnect the light for service. I have also needed to work on the lighting circuit and in this case I unplugged some of the fixtures and plugged them into an extension cord temporarily so I could see to work. Thanks for the comments

jeff-o (author)mark492009-06-19

Ha, actually, I did the same thing. I just ran outlets next to the lights and attached the outlets to a light switch.

lou_cyfer (author)2009-06-18

you are out of date, buddy !

in my shop, you can get "big Fluoros" with high-voltage driver-pcbs (like in laptops) already (no ballast, starter, etc needed). You even dont need the (lamp)-wires for starting; so you can used old burnt ones too!.
they cost 5E. (OBI, germany). I guess nobody knows, because they look so ordinary.
=> no flickering, light, everlasting, powersaving

mark49 (author)lou_cyfer2009-06-18

I am not familiar with these "high-voltage driver-pcbs", but I think you might be referring to the same thing I am. These ballasts that I used are electronic and do use a high voltage and high frequency that eliminates flickering. And if a lamp has died because the filament has burnt out these ballasts will still light it

kennyboy019 (author)mark492009-06-19

Oh, I know what he's talking about. I can't find it anywhere because I can't remember the name, but it uses a high frequency electro magnetic field to excite the gases in a fluorescent lamp. Lifespan is somewhere in the area of 100k hours plus because there are no cathodes to go bad, as the lamp is completely sealed. Pretty neat stuff. Great for areas where you can't easily access the fixture to replace bulbs

thematthatter (author)2009-06-17

why are your ballast going out? My $6 shop light from walmart is still working after like 6 years, and i have another one i bought used at a garage sell thats still kicking after 7.

mark49 (author)thematthatter2009-06-18

There has been a switch from magnetic ballasts to electronic ballasts in the past few years. Several of the cheap newer electronic brands seem to have very short life spans. All of mine were Sunpak brand ballasts. I don't know if your shop light would have an electronic or a magnetic ballast. The magnetic ballasts usually do last longer than cheap electronic ballasts but aren't as efficient and may allow the light to flicker. I have had some cheap magnetic ballasts that caused the tubes to burn out very quickly too. Also the cheap magnetic ballasts won't work in cold weather.

thematthatter (author)mark492009-06-18

They were magnetic, cause they have that hum, i dont know if electric ones have the hum

theRIAA (author)thematthatter2009-06-17

Maybe he uses his more. Nice Instructable, never thought of doing this.

kissiltur (author)2009-06-18

Very useful - I have a dodgy light fitting whose ballast has probably failed (bad installation - not mine!) and I would much rather not switch the fixture because it's so bloomin' heavy. Thanks.

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