ceiling fan/light with 2 sets of wires

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  #1  
Old 08-26-08, 02:37 PM
T
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Question ceiling fan/light with 2 sets of wires

I am trying to install a new ceiling fan/light in a bedroom which previously only had a light. There are two sets of wires in the junction box in the ceiling. Both sets of wires are (black, white and copper). THe new ceilng fan/light has 4 wires (black, white, green and white/black). Oneset of wires goes to the wall switch and I believe the other goes to the lighting in the upstairs bathroom as they are on the same breaker. I think the power is coming from the upstairs bathroom down to the bedroom. When I took the old light out, there was so much electrical tape on the wires I was unable to mark the wires as I disconnected. How do I reconnect the wires?
 
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Old 08-26-08, 03:45 PM
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When I took the old light out, there was so much electrical tape on the wires I was unable to mark the wires as I disconnected.
Gosh how I hate to hear that. Without knowing how the old light was connected, the job becomes 100 times harder than it needed to be.

We can't directly answer your question without more information, and more investigation on your part.

Do you own any electrical test equipment? It will be easier if you do. Do you still have the old light fixture? If you don't own any test equipment, the old light fixture can be used instead if you still have it.

Look at the switch wiring. Does it have one black wire and one white wire and one grounding wire connected to it? With no other wires in the box?
 
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Old 08-26-08, 05:12 PM
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The switch box has one black, one white and a ground wire. The ground wire is not attached to anything. I do have the old light. It has one black, one white and one ground. The only electrical tester I have is the old light bulb/socket with the white and black wires. When I touch the wires from the wall switch (at the switch and in the junction box) there is no electricity. When I touch the other set of wires in the junction box I have electricity.
 

Last edited by toddgiorgi; 08-26-08 at 06:26 PM.
  #4  
Old 08-26-08, 10:07 PM
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Okay.

One of the black/white cables at the ceiling is the power feed, and the other is a switch loop. Your first job is to figure out which is which. Here's how.

First, turn off the circuit breaker (not just the wall switch). Connect your old light to one of the black/white pairs. Pick either pair at random, but make sure that the black and white you pick come from the same cable. Then make sure that the other black and white wires don't touch anything. Then turn your breaker back on. If the light comes on, then you connected it to the power feed. If the light doesn't come on, then shut off the breaker again and connect the light to the other pair instead and repeat the test.

Once you've identified which cable is the power feed, then the other cable is the switch loop.

Now before we finish this up, you need to tell us how you want to control the fan/light. Do you have a remote control? Does your fan have pull chains? Do you want the wall switch to turn on both the fan and the light, or just the light? Since you only have one wall switch, a common approach (if you don't have a remote) is to operate the fan with the pull chain (independently of the wall switch) and let the wall switch control the light (independently of the fan). Is this what you want?
 
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Old 08-27-08, 01:02 PM
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The most common approach you stated, controling the light with the wall switch and the fan with the pull chain is the way I would like to set this up. I do not have a remote.

I have identified the wires which are the power feed, and which wires are the switch loop and I am pretty sure the wires coming from the wall switch are not the power feed. Now I just need to know which wires to put together.
Also, is the ground wire supposed to be hooked to something in the wall switch, or does it just hang loose.
 
  #6  
Old 08-27-08, 02:50 PM
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Okay, it's simple.

Connect power feed black to switch loop white, and to fan black.

Connect power feed white to fan white.

Connect switch loop black to fan white/black.

Connect all grounding wires together.
 
 

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