Man on a ladder holding a fluorescent light, getting ready to replace a fluorescent light ballast.

How to Replace a Fluorescent Light Ballast (In 6 Easy Steps!)

Often, we replace our fluorescent lights when they begin to flicker or flat out don’t work. But sometimes, it’s actually the fluorescent light ballast that needs to be replaced and not the lightbulb itself. What’s a ballast? According to the Lighting Research Center, a ballast “regulates the current to the lamps and provides sufficient voltage to start the lamps,” ultimately preventing sudden overheating and burn-out, which would undoubtedly occur without one.

In other words: if the fluorescent light ballast doesn’t work, your bulbs won’t work either. If you keep putting in new fluorescent bulbs and they keep burning out, it may be the ballast that needs replaced first. If you’re unfamiliar with how to do that, don’t worry – we’re here to help!

Gather supplies.

You’ll need the following:

  • Fluorescent Light Ballast (Be sure to get one that’s for the specific bulb that your light requires. This one is a T12, while this one is T8.)
  • Screwdriver
  • Wire connectors
  • Wire cutters and/or utility knife
  • Electrical tape
  • Ladder
  1. Turn electricity off.
    Go to your breaker box and turn off the power for the area you’ll be working on. Before you begin, turn the light switch on and off for that light to ensure that the power is not on.
  2. Remove light cover and bulbs. Often covers can simply be twisted or popped off, but sometimes need to be unscrewed. Use caution and common safety practices when climbing a ladder. Next, remove the blight bulbs from their sockets. Use caution here as well to prevent breaking the bulbs and possibly cutting your fingers. It’s vital to note that fluorescent bulbs can explode, so gently set them down on something soft (like a towel) and in a safe place for the remainder of the project.
  3. Remove ballast cover. Up until this point, it’s been fairly common knowledge, but here is where it may begin to be new territory for some. Once the bulbs have been removed, a metal cover becomes visible, which is the ballast’s cover. It can be removed by pushing the sides together or by unscrewing it, depending on how yours is put together. Pull the metal cover off and set it aside.
  4. Disconnect wires. This is where you get to pretend you’re a secret agent! Cut the wires attached to the old ballast, cutting as close to it as possible. Use the utility knife to strip the wires, exposing 1-2” of bare wire.
  5. Remove old ballast. Unscrew both screws on the ballast, typically located on either side of it. Once you’ve removed it, you can simply throw the ballast away.
  6. Install new ballast. Insert the new ballast. If not bare, strip the ends of the wires on the new ballast. Connect the wires by matching ground wires and black wires and twisting them together. Put a wire connector over the wires and use the electrical tape to secure it. Screw in the new ballast, replace the metal cover, install the fluorescent bulbs, and replace the light cover. Turn the power back on and boom – You’re back in business, and you just learned a new skill to boot!