3-way switch puzzle


Old 12-08-13, 05:40 PM
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3-way switch puzzle

Hi all,

In my garage, the light switch is is a really inconvenient place.

I want to add a 3 way switch but all the diagrams i find online do not seem to fit my situation. In my garage both the power and the light cable currently enter into 1 existing junction box, in which I want to swap the existing switch by 3 way switch, and add another 3 way switch in another area of the room.

I drew a diagram to describe the situation

Name:  3waydiagram0001.jpg
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Is is possible to just add a switch by solely linking it to the circuit using a 3-cable wire considering how my power + light is set up?

Thanks for your help
Old 12-08-13, 08:39 PM
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Yes it is possible, and relatively easy. All you need to do is run the new three wire to where you want the new switch....and make your connections as follows:
Turn power off at the circuit breaker or fuse
Wire nut all the bare or green ground wires together, and leave a "pig tail" whip ( single conductor) off of that wire nut to attach to the switch
Wire nut the white wire going to the light fixture to the white wire of the feed cable
Wire nut the white wire of the 3 wire cable to the black wire of the feed cable
Attach the black and red of the 3 wire cable to the 2 SAME COLORED screws on the three way switch
Attach the final black wire to the "common" labeled screw on the three way switch, also will be either brass or black colored screw on the switch
Connect the ground wire to the switch to the green screw
On the new three way switch, which should just have just a single 3 conductor cable, with ground....attach the ground wire to the green screw, attach the red and black wires to the two SAME COLORED screws again, just like the first switch, but attach the white wire to the "common" labeled screw of this switch
Turn power on, test switches....light comes on!

Or following your diagram:
Wire nut 10 and 20
Connect 11 to 30
Wire nut 21 to 51
Connect 50 to 31
Connect 52 to 32
Connect 53 to 41? Assuming #40 is your common
Connect 54 to 40? Again assuming # 40 is your common terminal
Connect 55 to 42

Mod Note: The re-purposed white needs to be marked at each end with black tape or magic marker to show it is now a hot conductor.

Last edited by pcboss; 12-08-13 at 09:01 PM.

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