3 way to 2 way light switch

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  #1  
Old 10-18-13, 02:56 PM
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3 way to 2 way light switch

Hi,
I bought a wemo wifi light switch and after removing my old switch I found out the wemo doesn't work with 3way lights.
So question is, how do I change a 3 way light switch to work with a 2 way switch?

I found some things online but not sure if it's safe to do this. The article said take one switch and wire nut the 3 wires together (2 blacks and a red wire) eliminating that switch. Then go to second switch and wire the red and black as 1 connection, and the other black by itself. (not including the green and white)
Does this sound safe to do this? I don't care if I eliminate the 1 switch or not.

The wemo switch has 2 black wires, 1 green, 1 white.
My wall has 2 black, 1 red, 1 white and the green/ground.

Any advice is much appreciated.
 
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  #2  
Old 10-18-13, 03:44 PM
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Welcome to the forums!

There's no such thing as a "2-way" light switch in American terminology. I'll assume you're asking about an on/off switch, since that's what you've bought and are trying to wire up. To do that you need to connect your new switch so that it will make and break the connection between the power coming in from the panel and the power feed to the light.

I found some things online but not sure if it's safe to do this. The article said take one switch and wire nut the 3 wires together (2 blacks and a red wire) eliminating that switch. Then go to second switch and wire the red and black as 1 connection, and the other black by itself. not including the green and white) Does this sound safe to do this?
No. That "advice" has no context. The color of the wire to use for each function in a 3-way switch system is at the discretion of the installer. There is no standard. In addition, the power from the panel may come first to the light, to the switch box that also has the feed for the light, or to the switch box that doesn't have the feed for the light.

First, a bit of the context: All 3-way switches have three terminals. Two of them are the two traveler terminals. They are usually bright brass. The third terminal is the common, or point, terminal. It should be a different color - usually black or very dark gray.

You need to find the two-wire pair that brings the power from the panel and the pair going to the light, or find the two-wire switch loop pair, and determine how they're connected to the two switches. Then we can tell you how to change the wiring to do what you want. Here's what you need to do to figure this out:

First, turn the power off, uncover both of the 3-way switches, and pull them out far enough to see all of the wires that enter each box and how they're connected. Don't disconnect any wires until we know what each one does.

Tell us the number of cables or conduits entering each box, the number of wires, by color, in each cable or conduit, and how each wire is connected.

My wall has 2 black, 1 red, 1 white and the green/ground.
Presumably that's one of your two switch boxes. The one where you want to mount your new switch? Even if you have wires pulled in conduit, it sounds like you've listed either too many or too few wires in that box. Double-check that one, tell us where each wire comes in and how it's connected, and do the same for the other switch.
 
  #3  
Old 10-19-13, 09:59 AM
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Thanks for the reply. I thought this would be a simple switch replacement, so I already removed the 1 switch. And the "advice" didn't say the wire colors, I was just letting you know what color they are.
I checked the other switch and it is the exact same. The switch has 2 black wires at bottom of switch, a red wire at top of switch, then a ground wire. In both boxes the white wires are tied together in back of box, not connected to switch.
Thanks again
 
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Old 10-19-13, 10:18 AM
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The switch has 2 black wires at bottom of switch, a red wire at top of switch,l
That isn't important and will vary with manufacturer. What is important is what color wire is on the common wherever it is located on the switch. Nash wrote:
The third terminal is the common, or point, terminal. It should be a different color - usually black or very dark gray.
And as Nash wrote:
You need to find the two-wire pair that brings the power from the panel and the pair going to the light, or find the two-wire switch loop pair, and determine how they're connected to the two switches.
 
  #5  
Old 10-19-13, 10:40 AM
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In both boxes the white wires are tied together in back of box, not connected to switch.
Excellent. Does each switch box have just one 2-conductor, 3-wire (black/white/bare) cable and one 3-conductor, 4-wire (black/red/white/bare) cable in ii? If so, this system is almost certainly wired so that the power from the panel comes into one of the two switch boxes and the power goes to the light from the other.

Post back with that information and with a description of the colors of the wires connected to each terminal on the switch that's still in place, and we should be able to give you the advice you need in one more reply.
 
  #6  
Old 10-20-13, 10:19 AM
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There are 2, 2 conductor wires. 1 has black and red, the other is black and bare. Then there is a cluster of white.
 
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Old 10-20-13, 11:33 AM
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There are 2, 2 conductor wires.
Do you mean two 2-conductor cables? A wire is always a single conductor.
1 has black and red, the other is black and bare. Then there is a cluster of white.
The whites are part of the cable assembly so what you actually have is one 2-conductor cable (black, white plus) and one 3-conductor cable (black, red white). Both cables shoulf have a bare ground.

Now we need to know how the wires are connected to the switch using the term common for the odd colored screw and traveler for the brass screws. Use descriptive names for the wires such as 3-conductor black or 2-conductor black.
 
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Old 10-20-13, 02:32 PM
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Ok, the cable with black, white and bare, the black wire goes to the colored screw.
The other cable with black and red goes to the brass screws, with red being on top of switch.
 
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Old 10-20-13, 04:31 PM
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with red being on top of switch.
The switch has no top or bottom. Only the color is important. Disconnect the 2-wire cable and measure between the black and white wire with your multimeter. Do you get 120 volts?
 
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Old 10-20-13, 10:18 PM
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the cable with black, white and bare, the black wire goes to the colored screw.
The other cable with black and red goes to the brass screws.
Is it connected that way at both switches?
 

Last edited by Nashkat1; 10-20-13 at 10:54 PM.
  #11  
Old 10-21-13, 02:01 PM
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yes, both switches are setup the same.
Is it possible to do without a volt meter? If not, I'll go get one.
 
  #12  
Old 10-21-13, 02:58 PM
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A $8-$15 analog (not digital) multimeter is a good tool for all sorts of checking but you can also improvise. Connect a receptacle to one of the two conductor cables and plug a lamp into the receptacle. If it lights you have found the hot cable.

To be clear you want to use a single location switch and abandon the switch at the other location. Is that correct? Does it matter at which location the new switch goes?
 
  #13  
Old 10-21-13, 05:12 PM
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Yes it's 120. I don't have to eliminate a switch, but thought it was necessary. And, don't care which ilocation is used for new switch
Thanks
 
  #14  
Old 10-22-13, 10:14 AM
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I don't have to eliminate a switch, but thought it was necessary.
From your description, you have the power feed in one switch box, the light feed in the other, and a traveler cable from box to box. If so you will have to bypass one of your existing switches.

Is it possible to do without a volt meter?
If I understand your description correctly, it should be. Try this:

Buy a blank cover for one switch box and decide which switch location you will eliminate. In that box, remove the switch and splice the grounds together, the neutrals together and the black wires together. Put a wire nut cap on the red wire. Fold everything into the box and install the blank cover.

In the other box, remove the existing switch. Splice the neutrals together and fold that into the box. Cap the red wire and fold that in. Splice the ground wires together and add the ground wires from your new switch. Splice each of the black wires from your switch to one of the black wires in the box. Fold the last of the wires in and mount and cover the switch.

Turn the power back on.
 
  #15  
Old 10-27-13, 12:19 PM
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That worked and the lights are on WiFi..
Thanks for the help, awesome forum.
 
  #16  
Old 10-27-13, 12:24 PM
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Good job. Thanks for letting us know the outcome.
 
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