How to Replace a Single Pin Fluorescent Light Ballast

Although not commonplace for lighting anymore, many single pin type fluorescent light fixtures can still be found in service. This type of light is easily identified by the use of a single brass colored pin positioned at either end of the 8-foot long florescent tube. Replacing the ballast on these fixtures is a quick job.

  1. Unpack the pin type ballast from the box and double check that the ballast is correct. Identification is easy, as there will be only six wires for a two light fixture. There should be a black and white wire--these are the power in connections--and two blue and two yellow wires. The blue wires are the high voltage power lines that go to one end of the bulbs and the yellow wires are the high voltage common or neutral wires.

  2. Remove the electrical power from the fluorescent light fixture. This can be done at the light switch, but it is highly recommended to do so at the circuit panel box by switching "off" the correct breaker or pulling the power fuse.

  3. Remove the long fluorescent bulbs from the fixture and set them aside so they will not break. Use the screwdriver and remove the two long covers that conceal the wires and ballast.

  4. Unscrew the two wire nuts that are covering the power feeder wires to the light fixture. These should be a black and white wire. Allow the feeder wires to hang out of the way.

  5. Use the wire cutters and cut the two blue and yellow wires one foot from the ballast. Allow these wires to hang out of the way also. Remove the ballast from the fixture by unscrewing the keeper nut at one end of the metal ballast. Do not lose this small nut as most ballast replacements do not contain a spare nut.

  6. Install the new ballast into the light fixture. The wires on the replacement should already be stripped back to reveal a bare copper end. If not use the wire strippers to reveal at least one inch of bare copper. Do the same to the wires that are going to the light fixture holders you had cut in Step 5.

  7. Using the wire pliers tie the power feeder wires to the black and white wire of the ballast by twisting the pairs together and cover the bare copper joint with a wire nut. Match up the same colored pairs, blue and yellow, from the new ballast to the light holding fixtures. Again cover the bare copper joints with a protective wire nut.

  8. Replace the light fixture covers to hide the wiring and the new ballast. You may have to "coil or fold" the long wires around themselves in order to keep them from being pinched between the cover and metal fixture housing.

  9. Install the long fluorescent tubes in the light holding fixtures and apply power.


  • Dispose of the old ballast properly as some older lighting ballasts may contain harmful chemicals. Consult local disposal regulations.