Dimmer switch when there are two different light switches


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Old 02-18-16, 08:01 PM
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Dimmer switch when there are two different light switches

Hi,

I'm really new to this kind of stuff, but I've recently installed a few dimmer switches and then today, for the first time, installed a pendant light where a recessed can light previously was (go me! haha).

Anyway, in the hall coming from the garage of my house, there's a light switch for the ceiling light right as you come in the door. Then near the kitchen, there's a light switch for that same light.

What will happen if I put a dimmer on just one of those switches (the one near the kitchen preferably). Will it work? Is doing it any different than the other dimmers I've added? What will happen if say I have the light dimmed, and then someone flips off the light from the other light switch over by the garage? And what happens when they turn it back on? Will it turn on to the amount dimmed that the dimmer on the other end of the hallway is currently set to?

It seems like it shouldn't be an issue, but I wanted to check before I try it, since it is electricity after all, and I'm still new to all of this.

Thanks!
 
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Old 02-18-16, 08:13 PM
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Welcome to the forums.

You have two switches controlling one light. That is a common setup and is called a three way circuit.

They do make dimmers that replace one of a pair of three way switches but the wiring is not always straight forward. If you intend to use one existing switch then you need to buy a three way dimmer that works with an existing switch.

My experience..... buy a three way dimmer and its companion dimmer. Will cost a little more but be easier to install.
 
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Old 02-18-16, 08:19 PM
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Thanks for the quick reply!

This is the model I've been using on all my other dimmers, and it does appear to support three way...

Leviton 6674-P0W SureSlide Universal 150-Watt LED and CFL/600-Watt Incandescent Dimmer - Wall Dimmer Switches - Amazon.com

So am I to understand that when I pull off my wall plate and check everything back there, there may already be a 4th wire (like the one on the back of these dimmers that I normally don't use?) that is enabling the three way circuit? If the wire is already there, I don't think I'll have any trouble doing it... As long as I don't have to add extra wires myself.

I'll have to read the instructions some too, but asking helps me get a little insight ahead of time :-)
 
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Old 02-18-16, 08:28 PM
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Yes.... you will find three insulated wires and possibly a ground wire on the switch.

The key to working with three way switches is that you MUST identify the common terminal. It will usually be dark colored or black while the other two will be the same brass coloring.
 
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Old 02-18-16, 08:35 PM
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Thank you! I'll make sure to look at the instructions and I'll also just take a look for myself behind the plate to make sure what I'm seeing is what I'm expecting... if I have any questions I'll be back.
 
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Old 02-18-16, 08:46 PM
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Sounds good.... we'll be here to help you.

As long as you keep the common wire identified.... you'll be in good shape.
 
 

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