Intro: Retrofitting a CFL Light Fixture to LED
Well, here goes - this is my first Instructable.
When we bought our house several years ago and updated all the light fixtures from old style to a look more consistent with our taste, two fixtures we selected used the compact fluorescent tubes as shown. Unfortunately, these tubes contain Mercury, are expensive ($7 each at the orange big box store), and have not lasted as long as their advertised expectancy. When yet another set of bulbs died after only a couple of years, I said, "That's it!" and looked for an alternative. Replacing the fixture is an option, but picking a style between two people proves to be very difficult. So, being an Electrical Engineer looking for projects, I came up with this retrofit. As usual, the standard disclaimers apply. Obviously, the fixture warranty is void. Use common sense when working with electricity (TURN IT OFF), I am not responsible for anything that happens if you choose to try this, and practice proper precautions when working with tools and wiring.
Also, please consult your local wiring codes and laws. Some countries may prohibit this type of modification as it would violate regulatory requirements.
Now that the formalities are out of the way, here goes.
Step 1: Gather Your Supplies
Prior to starting the project, I needed to figure out how I would do the retrofit. I had thought about buying a standard brass colored table lamp socket and fashioning a bent metal bracket to secure it. But, during a visit to the orange box box store to purchase the LED light bulb, I found these parts which are meant for building and/or repairing lamps. And....the light bulb (in my head) turned on. The lamp socket pictured here would be perfect, with one minor modification!
Step 2: Disassemble Fixture
First, turn off power, remove the fixture from the ceiling, and disassemble it by unscrewing the ballast and lamp sockets. Be sure to use caution when removing wire nuts, use eye protection in case debris falls from ceiling and/or junction box, and make sure power is TRULY off. I have had some occasions where two circuits reside in a given box. One never knows how a previous owner or house builder wired the place!
Step 3: Prepare Lamp Socket
As shown in the photo, I had to make a minor modification to the lamp socket. The threaded bracket is meant to hold the socket above the wired base of a lamp. I removed the screw, used two pairs of pliers to bend the bracket, and then reinstalled it. You need to achieve an angle of "the light bulb fits within the base and cover of the fixture". In this case, I used my Italian cooking method of "yeah, that's about right" to set the angle of the bend.
Once reassembled, add the smallest threaded nipple rod from the package and one retaining nut to the socket assembly as shown. Of course, depending on your fixture, you may need to use a different length nipple.
Step 4: Mounting and Wiring
Harvest the black and white wires from the ballast. Take note of their condition. If they are frayed or look damaged in any way, take the safe route and purchase some new wire. 16AWG or 18AWG stranded will be sufficient as the power consumption is minimal.
Strip back the insulation and secure the wires to the socket. The BLACK wire MUST fasten to the terminal for the inner tab of the socket and the WHITE wire to the threaded outer shell. This way, you will have less of a chance of shocking yourself should you accidentally touch the threaded base of the bulb while installing it into a live fixture. However, see my earlier disclaimer of making sure the power is OFF to the fixture first!
Secure the socket assembly to the fixture by selecting a hole which will centrally locate the bulb within the fixture. On my fixture, I located the bulb slightly off center within the fixture to avoid an interference with the thumbscrew that secures the fixture to the ceiling. Feed the nipple through one of the available holes in the fixture and secure with another nut. If no holes are conveniently located, drill a new one.
Feed the wires through the nipple. Use caution not to chafe the insulation or pull too tight as to put strain on the terminals. Leave a small service loop in the wires near the socket. One step I forgot was to add an Underwriter's Knot in the wires per the attached photo. However, I think in this case the fixture should be okay because unlike a table lamp, this fixture will be affixed to the ceiling and not subject to having its power cord pulled or moved once installed.
Be sure to secure the ground wire if it came off during the initial disassembly. I reused a ballast mounting screw and lock nut to secure the ground wire.
Step 5: Reinstall Fixture
Reconnect fixture using wire nuts. Take your time and use care to make sure wires are safely tucked into ceiling box or within mounting provisions of the fixture so they will not get pinched or damaged when the fixture is secured to the ceiling. Secure fixture in the reverse order you removed it from the ceiling. In my case, a threaded nipple extends from the fixture mounting plate previously mounted to the ceiling box which accepts a thumb screw. You can see this thumb screw under the light bulb.
Once everything is tidied up and secure, turn on the power and test your newly retrofitted LED powered light.
My fixture now produces a similar number of lumens using less wattage, and it will hopefully not need a replacement bulb for several years.
I hope you enjoyed my first Instructable.