Funky wiring for bathroom fan complicates timer installation

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Old 10-07-09, 06:01 PM
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Funky wiring for bathroom fan complicates timer installation

Hello-

I'm looking for advice on a wiring issue for our bathroom fan. We want to replace the current on/off switch with a timer, and the timer switch has four wires: black, red, white, and green. About the only electrical experience I have is replacing receptacles and switches, but this particular switch is in a 170 year old house and isn't wired in the simple and straightforward ways that I've previously seen.

Our current set-up has two side-by-side switches in one panel, with the left switch used for the fan & two lights, and the second switch for a heat light. When I opened up the receptacle what I found were 4 black copper wires connected to the Fan/light switch: 2 in the back entering into holes in the back of the switch, and one each on the left and right terminals. The hot wire comes in to the left hole in the back, and was wired via the left side terminal to the left side terminal on the heat lamp switch (like a bypass?). The two black wires on the right side of the switch work the lights and fan (though I'm not sure which is which).

SO-my questions:
1. Can I incorporate the bypass into the wiring scheme of the timer switch (e.g. by wiring the hot-in wire with the red (hot) wire of the timer and with the bypass wire connecting the two switches)?

2. Is there something I should connect the white wire to? There is a white wire connected to the heatlamp switch, so perhaps that's the ground the fan switch is using?

3. If I want to keep the lights and fan tied to the same switch, can I simply splice all three together?

Thanks for your responses!
 
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Old 10-07-09, 06:31 PM
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If the white is attached to one of the switches currently it is being used as a hot.

Your timer is probably using the white as a neutral for the timer circuitry. The black and red are like the 2 screws on a single pole switch.

The bypass that you are asking about is most likely being to join the incoming power to the second switch along with supplying power to the first switch.
 
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Old 10-07-09, 06:34 PM
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The timer did not come inside one of those hard clear plastic containers with a folded up paper instruction sheet?

Also, is it possible you got a timer switch meant for a 3-way circuit, instead of for a regular single pole switch?

I just went through this very 4-wire (including red) thing, with a dimmer the old man bought, not knowing it was for a 3-way circuit. So then he quickly hopped in his car to the nearby hardware store and got me the correct dimmer switch that only had 2 wires. Can't say for sure that is your case, but it may be.
 
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Old 10-07-09, 06:39 PM
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Just a note do not disconnect unless of your sure of the relationship of the wires on the switch with 4 wires. What you have is two pairs of wires that to reduce confusion pigtailed together. Generally the backstab nearest to the screw is connected to it so those wired should be wired nutted together with a pigtail.
 

Last edited by ray2047; 10-07-09 at 07:01 PM.
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Old 10-07-09, 06:39 PM
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Funky fan wiring cont'd

It did come in a clear plastic pack--the intermatic EI210 Electronic in-wall countdown timer. It says specifically that it's good for bathroom fans, and that it can "replace any* normal indoor wall switch" The star indicates that it needs a neutral conductor.

Still not sure regarding the questions I posted earlier
Originally Posted by ecman51` View Post
The timer did not come inside one of those hard clear plastic containers with a folded up paper instruction sheet?

Also, is it possible you got a timer switch meant for a 3-way circuit, instead of for a regular single pole switch?

I just went through this very 4-wire (including red) thing, with a dimmer the old man bought, not knowing it was for a 3-way circuit. So then he quickly hopped in his car to the nearby hardware store and got me the correct dimmer switch that only had 2 wires. Can't say for sure that is your case, but it may be.
 
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Old 10-07-09, 06:45 PM
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I think you've nailed the ID of the wires-I spent the time to figure out what each one was doing, and the backstabs are definitely connected to the side terminals on the same side...

Originally Posted by ray2047 View Post
Just a note do not disconnect unless of your sure of the relationship of the switch with 4 wires. What you have is two pairs of wires that to reduce confusion pigtailed together. Generally the backstab nearest to the screw is connected together
 
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Old 10-07-09, 06:47 PM
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The old man gave me that other switch! I have it here in my hand and just read the instructions - and this may apply with your timer. I have 4 wires = the green ground wire, 2 reds and a black. It says how to use this switch for 3 way. But then also tells you that you can use it with with a standard one way switch, and if so, you need to cap off one of the red wires.

So you really need to find out what applies to yours.
 
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Old 10-07-09, 07:57 PM
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2. Is there something I should connect the white wire to?
Yes a neutral but it doesn't seem you have a neutral.
There is a white wire connected to the heatlamp switch,
This is not a neutral. It is the power return wire for the heat lamp. It should have been remarked black or any color but white or green.
so perhaps that's the ground the fan switch is using?
No. For a variety of reasons. I think you are confusing ground and neutral. Neutral is a current conductor used to complete a circuit. Ground is for safety only and is green or bare.

You need a neutral for the timer you have. If the box doesn't have one you will need to rewire or use a different timer. Because you have a fan motor it may not be advisable to use a timer without a neutral.
 
 

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