Add third switch (power at light)


  #1  
Old 09-04-20, 02:12 PM
J
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Lightbulb Add third switch (power at light)

Hoping someone can help. I have an upstairs hallway with a switch at the top of the stairs ( Switch A) and one at the bottom (Switch B). I want to put another switch further down the hallway. I have 14/3 wire already at the new box and to the attic so I can connect it to A. My struggle is the current system is wired like below:
<img src="https://cimg3.ibsrv.net/gimg/www.doityourselft.com-vbulletin/725x431/ace76cde_4496_47ff_a591_f02b6f12b210_4bab525dbdf08bc9cac32989e294eaeec3e4754b.gif" width="725" height="431"/>
with the middle switch being A and right hand being B. I want to install the new switch C and connect to A. Can I do that? I know I'd need to replace A with a 4way switch but I'm confused on how to connect C to it.

Apologies if I'm not explaining well. Thanks for any help.
 
  #2  
Old 09-04-20, 05:13 PM
J
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You can connect into either of the existing switches. the connection will the same no matter which switch you tap into.
The existing switch location. will become the four way and the the new location will be the three way.
I will describe 14/3. If your circuit is 20 amp then 12/3 is needed.

Run 14/3 from existing switch to new switch.
At existing switch
Take wire off common and connect to wire of same colour in new cable.
Take two wires off traveller terminals and connect to one set of 4 way screws.
Connect two remaining wires from new cable to other set of 4way screws.

At new switch location.
Connect old three way the same as it was at old location.

 
  #3  
Old 09-04-20, 05:30 PM
J
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Thanks much. I'll give this a try tomorrow.
 
 

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