Ceiling fan/light to regular fixture fiasco

Old 07-21-02, 10:16 PM
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Unhappy Ceiling fan/light to regular fixture fiasco

Today I attempted to replace my old ceiling fan/light with a standard drop down light fixture on a simple dimmer switch. The old combo was controlled by a single switch. The switch had a reostat to turn off/on and control the fan speed and a reostat to turn off/on and dim the lights. The wiring coming out of the ceiling is just one black, one white, and one green. The wiring coming into the switch, however, is three sets of white/black/green. The old switch had one black and one red wire coming out of it on top and one yellow wire coming out of the bottom. I did the novice thing by disconnecting everything without noting what was connected to what. Now I have no idea which of the three sets of wires does what.

I have narrowed down the hot wire to the black on pair one (left side set). Since I don't own a volt meter, I trialed and errored until I found a combination that would bring power to the light when the circuit breaker is turned on. If I connect the left set and middle set of blacks together and connect them to one wire on my single pole dimmer and then connect the left and center pair of whites together and connect to the other wire of my dimmer (I connect green to ground), when I turn back on the power at the breaker, the light goes on and nothing my dimmer does will turn it off. I have also tried to find the right combination of two of the blacks (center and right) to one wire on the dimmer, one black (left) the other wire. Doing any combination of blacks alone gets me no light at all.

One last note, I have for the moment capped off all wires in the wall (two blacks randomly tied together, one alone, all whites together. Now I notice that I have lost power to a single outlet in the adjacent room. The house is approximately 37 years old but the ceiling fan is less than ten years old (I have been told).

Sorry for making such a muddled mess of this. My head has had it for the day.
Old 07-22-02, 06:31 PM
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First of all, it is very important to stop random guessing. You could end up with something you think works okay, but is very dangerous to your safety and the safety of your house. You are dealing with deadly power and wires that can burn your house down. Please use caution.

I assume you have identified all the wires in your ceiling, not just the ones "coming out" of the ceiling.

First, go to Home Depot and buy a $2 neon bulb circuit tester.

Then shut off the breaker and separate all the wires at your switch box. Chase the kids out of the room and turn the breaker back on. Carefully use your circuit tester to test each pair of black and white wires. Only one pair will light your tester. This is your power cable. Call this cable "P".

Now go turn off the breaker again. Select one of the other two cables. Connect this to the power cable, black to black and white to white. Use wire nuts. Then turn the breaker back on again. Go plug a lamp into the receptacle that lost power. Does this receptacle work again? If so, then the cable you selected provides downstream power. Call this cable "D".

But if the experiment in the last paragraph did not make the receptacle work again, then use your circuit tester to test the black and white wires in the ceiling. If your tester lights up, the the cable you selected in the last paragraph is the light cable. Call this cable "L".

Shut off your breaker again. Disconnect the power cable from the cable you had connected it to, and connect it to the other cable instead. Again, black to black and white to white. Repeat the tests in the previous two paragraphs. You should get the opposite result.

Shut off your breaker again. You have now identified all three cables in your switch box, "P", "D" and "L". Make the following connections, using wire nuts:
  • Pb (cable "P" black wire) to Db to one black wire on your dimmer.
  • Pw to Dw to Lw.
  • Lb to the other black wire on your dimmer.
  • All grounding wires to each other.
At the ceiling, connect your new light to the wires, black to black and white to white and ground to ground.

Turn on your breaker again. Test and report back.

P.S. Be sure to make excellent connections and pack the wires carefully back into the box. If you're not sure how, I suggest you read a good book on home wiring. A novice should not attempt any electrical work without having read a book or two. There are many safety considerations that may not be obvious to you.
Old 07-22-02, 07:07 PM
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Thanks for the tremendous advice

Mr. Nelson:

Thank you very much for the very detailed set of instructions. I realized after reading them and then reviewing my own post that I had left out some of what I had already done and was very happy to see that I had followed your recommendations in a number of ways already.

As to the problem, the first thing I did today was purchase an inexpensive multimeter to test for the correct pair. I had guessed correctly it showed but I felt much better to see it proven. I also picked up another dimmer just in case I had somehow blown the first one. I spent a large portion of last night reading threads about dimmers and wiring in general and was anxious for daylight so I could flip off the breakers and try again. Per your instructions I connected the Pb and Db wire to one dimmer switch wire , and the lb to the other dimmer switch wire. All grounds are connected together (including the dimmer ground) and all whites are connected. And what do you know, success all around. The dimmer works, the outlet works, everything is sealed correctly now and I am much happier.

By the way, I truly appreciate your mention of safety issues surrounding electrical jobs. I have some experience with plumbing and sprinklers but electrical scares me. I have a very basic book from Home Depot but before you replied, I was very close to just biting the bullet and calling the electrician. And for anything more than this, I will do so.

Anyway, thanks again. The job is complete.
Old 07-22-02, 07:18 PM
Join Date: Sep 2000
Location: United States
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I love a happy ending.

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