I have a fixture that uses one 36" T12 lamp. The recommended replacement ballast is a GE140RS120DIY. I am unable to find that ballast. I purchased a GE240RS120DIY ballast and wired it in. I wire nutted the two yellow wires with one nut to a wire. The new ballast is for two 48" lamps vs. one 36" lamp. It won't light and I'm wondering the reason why. Is there a way to wire it so it will work? Right now I'm two red to one end, and two blue to the other end of the 30 watt lamp.

  • Why not trade the whole thing in for an LED shop light? They cost about the same as a replacement transformer, use less wattage and should last much longer. They also avoid the problem of breakage and disposal of mercury containing fluorescent tubes.
    – bib
    Feb 27, 2016 at 14:08
  • Or simply an LED "tube" that fits into the lampholders, and rewire the lampholder on one end to supply 120v direct (per the tube's instructions). Of course this requires a non-shunted lampholder on the 120v end, Feb 27, 2016 at 15:37

2 Answers 2


Many ballast can be connected to 1 or 2 lamps some different lengths. The wiring may be different than your original (colors) look at the picture on the front of the ballast if it only shows connections for 2 lamps it probably will not work with just 1 lamp. This ballast should work found on line 13$. Fulham Fluorescent Electronic Ballast 120V for for (1-2) F32T8 (2) F25T8, F32T8, F25T12, F30T12, F3... by Fulham


You're wiring it contrary to its wiring diagram (on the label and on the spec sheet, found by googling GE240RS120DIY (you misspelled the part number). A single F30T12 is also not supported by that ballast.

Look for other ballasts which will support that bulb such as the GE240RS-MV-N.

You can also look for ballasts which take T8 bulbs. T8 bulbs will physically fit in T12 fixtures, however they do need a matching T8 ballast.

Edit: BETTER YET, get an LED "tube" replacement. It looks like a fluorescent tube, but it's made of LEDs. Here's the gotcha. Some of them, you rewire the fixture to put 120v directly on the pins of the ballast (called direct-wire). Others are "plug and play", meaning they cope with the weird voltages that come out of a ballast, and expect you to leave the old ballast in place. This is marketed as a time-saver, but is worse than useless if your goal is to get rid of the ballast entirely. You want 'direct-wire' if you go that way.

Your fluorescent tube has 2 pins on each end. Look closely at the sockets aka lampholders aka "tombstones". There are non-shunting and shunting types. A non-shunting lampholder has 2 pairs of stab connections, each pair goes to one pin on the bulb. A shunting lampholder allows only 1 pair, and shunts the two pins together internally. Rapid and programmed start ballasts use non-shunting, that is, 2 wires to each lampholder. Instant start ballasts use shunting lampholders (or non-shunting that you have jumpered) and have 1 wire per lampholder. If your lampholders are shunting, and your ballast supplies 2 wires to each tube end, you need to replace them with non-shunting. This is no big deal, they are pretty standard and cost between 60 cents and $3. A direct-wire LED conversion may require a non-shunting lampholder on one end or both.

  • Wolf, I would like to say thank you for all of your information. As long as I've been at this, fluorescent fixtures are still a mystery to me (or at least when they aren't working). This fixture is in my own home in a dropped ceiling that I'm going to eliminate one of these days. I replaced the ballast and everything is working. The info on T8 substitution and shunting vs non-shunting tombstones is something I need to know. I really do appreciate your help and am sorry I didn't respond more timely. This is my first knowledge of Stack Exchange. Guys like you make it a very valuable resource.
    – builder
    Mar 9, 2016 at 16:45

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