How to Change a Balast

An assumption is that the question to be answered in this article is; "How to Change a Ballast in a Fluorescent Light?" The word, "ballast" has two l's and occasionally needs replacing in fluorescent fixtures.
Changing a ballast is not a difficult task as long as the fixture is taken apart slowly to avoid breaking the bulbs and cover. Care must also be taken to connect wires to the new ballast in the same way they were connected to the old ballast.

Difficulty: Moderate

Instructions

Things You'll Need:

• Step Ladder
• Appropriate Sized Slotted-Head or Phillips-Head Screw Drivers
• Pencil and Paper
• Electrician's Pliers with Insulated Handles

Removal of the Old Ballast

1. Turn the power off at the breaker box or at the main disconnect switch to the house.

2. Remove the cover from the fluorescent light. This is usually done by pushing up and out on one side of the cover to lift it off of the retaining channel. After one side is loose from the fixture, move the cover to a vertical position and lift the other side off of its retaining channel.

3. Remove the bulbs by turning them approximately 1-quarter turn to align the pins with the slot in the bottom of the sockets. Once the pins are aligned, pull down on the bulbs gently and slowly. Place the bulbs in a secure area where they will not fall or get stepped on.

4. Remove the wiring channel cover by squeezing it to clear its retaining track. Some channels are fastened with screws which can be removed with a Phillips-head or a slotted-head screw driver.

5. Before disconnecting any wiring on the ballast, draw a wiring diagram on a piece of paper so that you can use it as a guide to connect the new ballast. After the diagram has been completed, disconnect the ballast wiring by unscrewing the wire nuts. Once the wire nuts have been removed, finish untwisting the wires using a pair of electrician's pliers with insulated handles.

6. Finish removing the ballast by loosening the nuts that attach it to the fixture.

Purchase and Installation of the New Ballast

7. Either record the number on the old ballast or take it with you to purchase the new one. It is important that you buy the right replacement. If you cannot match the number on your old ballast with one in store inventory, ask a clerk to help you. Your ballast might have been replaced with an improved model, particularly if your fixture is old.

8. Attach the new ballast to the fixture with the previously removed nuts.

9. Reconnect the wires using the wiring diagram and the wire nuts.

10. Reassemble the fixture and turn the power back on.

Tips & Warnings

• All fluorescent fixtures are not made in the same way. Required disassembly steps may vary from those described in this article.
• If a fluorescent bulb is broken, mercury gas will escape and should not be breathed. Be careful not to touch bare wires together on the old ballast. it may have a stored electric charge which is capable of shocking or causing burns.

References

• Home Wiring. Rex Cauldwell. 2000