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Discussion Starter · #1 · (Edited)
I removed a broken switch and am now unsure where to place one of the wires in the new switch.

Apparently there are three switches involved in this circuit. 2 of the switches have two common wires and two traveler wires (though only
1 common is shown in the attached figure for both of these switches (these two switches have three wires attached to them). I understand that these 2 switch setups are used in order that one can turn a light etc. on and off from two different locations.

What I find confusing is that there is apparently another switch involved. This switch has two wires, one of which is either a common or a traveler wire in the middle switch below. What is the purpose of this setup? Are there any online references that someone could cite for such a switch configuration? And most importantly, where does the wire from the 2 wire switch go (common or traveler)?


Note: The wire on the top right of the switch on the right does not necessarily go to the light as indicated. I am not sure where that wire goes. I do however know that the wire on the bottom right of the switch on the right foes either to the traveler or the common of the middle switch).




Thank you for any suggestions that you might be able to offer.
 

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If there are 3 switches controling the same light(s), 1 switch is a 4 way and has 4 wires, 2 from 1 three way switch and 2 from another three way switch. When you say one switch has 2 commons, probably that is a hot in and a hot out with a pigtail to the switch common.
 

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retired framer
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I removed a broken switch and am now unsure where to place one of the wires in the new switch.

Apparently there are three switches involved in this circuit. 2 of the switches have two common wires and two traveler wires (though only
1 common is shown in the attached figure for both of these switches (these two switches have three wires attached to them). I understand that these 2 switch setups are used in order that one can turn a light etc. on and off from two different locations.

What I find confusing is that there is apparently another switch involved. This switch has two wires, one of which is either a common or a traveler wire in the middle switch below. What is the purpose of this setup? Are there any online references that someone could cite for such a switch configuration? And most importantly, where does the wire from the 2 wire switch go (common or traveler)?


Note: The wire on the top right of the switch on the right does not necessarily go to the light as indicated. I am not sure where that wire goes. I do however know that the wire on the bottom right of the switch on the right foes either to the traveler or the common of the middle switch).




Thank you for any suggestions that you might be able to offer.
Are you sure the extra switch is not at the box that has the power coming in?
 

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Discussion Starter · #5 ·
Thank you Nealtw for your reply.


I am unable to comment on where the wire that was not attached to the middle switch comes from or goes to. My guess would be that it must be
a hot wire (from the fuse box though I cannot verify this).


I can clearly see that the switch on the right has a wire that goes to the middle switch. I am sure whether it should go to the traveler or common port.
 

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Connect the black and red from the same cable to the two traveller screws.
Connect the other two black and the one from the other switch together and to the common screw using another pigtail like is on the right switch.
 

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Discussion Starter · #11 · (Edited)
joed, the wire with the orange oval goes to common? I should attach this wire to the side screw on the common?


The middle switch was labeled with two common on the bottom. (The red and green ovals in the above figure.


Yes, this setup was fine until the switch broke. From what I remember this setup allowed us to turn on the lights in this bedroom.
 

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Discussion Starter · #14 ·
joed, I agree. The wire with the orange oval is hot and I assume that the common wires are cold (if disconnected as they should go to the light). wouldn't the simplest and surest way to make absolutely sure about this would be to buy a voltage sniffer? If the common wires when disconnected were cold (and given we know that the wire with orange oval is hot), then the wire with the orange oval should go to the traveler terminal.


Yes, I intend to purchase a switch that will allow up to 4 traveler wires to be backstabbed clamped. I feel more confident with this wiring than with a straight backstab.
 

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Discussion Starter · #16 ·
The middle switch has three screws (1 common , 2 traveler). Yet, there are

4 backstabs ( 2 common, 2 traveler). Originally, there were 2 backstabbed common and 2 backstabbed traveler. The wire with the orange oval either used one of the traveler screws or the common screw.


What possible purpose can all of these switches be fulfilling? I understand having 2 switches to turn a light on/off from two locations. This is a very helpful feature. For example, how else could you wire a staircase with a light?
Yet, three switches to control a light does not make any obvious sense to me. Why would someone have a wiring with the 2 switches approach and then add in another 2 wire switch? This is very unclear to me. Are there any url references for this switching pattern?
 

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Discussion Starter · #18 · (Edited)
Actually, that is a very good point.


The switch that I want to buy for this replacement only has room for 2 wires on the clamps. The clamps hold 2 wires. With the travelers, there are 2 traveler screws on the new switch with room for 4 wires in total in the side clamps.


Thank you Nealtw, that is the way that I understand it as well. the 3 way switch would be to the left of the picture with the right switch with the orange oval.


I think that I do have the logic correct. The wire with the orange oval should go to the common if both the common and this wire are both hot (if the common were disconnected from the switch), otherwise the wire should go to the traveler.


So I need to purchase a non-contact voltage sniffer. Any suggestions?
 

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It switches something. It may have switched a receptacle at some time in the past. Or may have switched half a receptacle. If someone swapped the receptacle and didn't cut the tab then the switch would do nothing.
I am beginning to think this is a three way switch even though it has four holes. How many screws does it have?
 
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