bathroom fan

hello: currently I am adding a bathroom ceiling fan to a house with aluminiun wiring. The light for the bathroom is on the wall, I disconnected the wire from the light to the switch, pulled the wire out up to the attic and cut it, now there is 14 guage wire from the switch to the attic. I put a junction box in the attic where the wire from light, wire from switch and wire from fan all join. I joined all three black together and all three white together, then I joined the three ground and a peice of copper wire together and ground the copper wire to the box. When switch is off light is on a little and the fan is going, when switch is on light is on but fan is off. Any help wounl be emensly appreciated thanks.

 

I'm afraid you're going to find this answer a bit hard to swallow. You are unfamiliar with a wiring technique known as a "switch loop."

Sorry to tell you this, but you cut into a switch loop. There is no power in a switch loop. When the light switch is off, the fan and light are in series and neither is getting proper voltage. When the switch is on, you short out the fan (giving it no voltage at all) and the light is getting all the voltage.

The problem is that the source of the power is in the bathroom light, not in the switch.

Is this a exhaust fan or a paddle fan? I will assume an exhaust fan. Do you want the switch to operate both the fan and the light at the same time? I will assume the answer is yes.

To correct this, do the following (using proper aluminum connectors):[list=1][*]Open up that junction box and reconnect the cable from the light to the cable from the switch, leaving the fan out of it. This restores things to exactly as they were before you began.[*]Run a new cable from the light box (I hope you can access it) to your new junction box.[*]At the light box, connect your new cable to the same two wires that your light is connected to, without disturbing any of the other connections.[*]At your new junction box, connect your new cable to the cable to the fan.[/list=1]Post back with any questions. It is extremely important to use the proper connectors for any aluminum to copper connections.

 

John I'm not sure you are allowed to run a parallel cable from the light to the juction box even though it will work. It might be better idea to replace the cable with a 14/3.

 

thanks for the help; Yes I want to use the switch to operate the exhaust fan and the light. I think I should be able to get another wire down through the wall, do I then just attach it to the same two screws on the switch the light screws are on? What would be the advantage of using 14 3 wire?
thanks again

 

devin

John Nelson's post clearly explains the easiest way to make this all work. Carefully reread it and if you cannot follow his plan, I would suggest calling in a pro.

Great care must be used with aluminum wiring and there are special methods for copper to aluminum connections.

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joed

In order to have 'parallel conductors', both ends have to terminate in the same place.

 

upon rereading the post I realize I read it wrong the first time. oops. I am using an anti-oxidant and also special grommets. thanks for the help guys

 

fan works great, wish I had spent more money on one that is a bit more quiet. thanks for the help everyone.