Complicated 3-way setup


Old 12-07-14, 12:57 PM
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Complicated 3-way setup

I have a 2 3-way switches with 4 cables in each box. Cable 1 is the typical 3-wire, cable 2 is the 2-wire to the light, cable 3 is a 2-wire power cable and cable 4 is feeding outlets I think.

So there are two boxes, two lights and two power cables. Switch 1 and switch two have two travellers (3-wire red/white), a power connection (black) and one other black wire which must be the light and a common connection (black). Each switch has five wires.

So how the heck is the 2nd switch controlling the first light when there are two power cables?
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Old 12-07-14, 01:17 PM
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Welcome to the forums! I'll hate myself for asking, but how were the switches wired before? What are you doing to the switches that require maintenance? Changing switches, adding lights, etc? This is the simplest three way set up with power coming at one of the switches. Pictures of each of your switch boxes with the switches pulled out along with the other wiring, power off would help us help you.

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Old 12-07-14, 01:37 PM
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I was changing to Decora switches and thought I was doing Monkey See/Monkey Do when changing over, but the monkey failed the test. My setup looks like this one except that the second box has a light and a power cable too.
Old 12-07-14, 01:46 PM
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You should be doing monkey - see monkey do. The key is the same wire must always be on the dark/black colored screw regardless of where it ends up on the switch. There is no top or bottom or side to a three way switch.... only the common is important.
Old 12-07-14, 02:31 PM
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You are right, this is probably one of the most complicated things you can do in residential wiring. Especially DIY. Sounds like a 3 way setup, and at the same time, providing power for other use to 2nd 3 way box, or providing power for other use at both 1st and 2nd 3 way box.
I would isolate the lights first, and then ask how to tap off for receptacles or other lights.
Find the source at one of the 3 ways. Hot will go to marked terminal. This is most important.
Find cable going up to light. Hot will go to other 3 way marked terminal. Travelers will be connected.
Once you have this correct, power can be tapped, but you will have to post back for how to do it after the basics are fixed.
Old 12-07-14, 04:25 PM
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Yeah, the outlets are the least of my worries. It looks like each switch is turning on it's own local light as well as providing power to the light in the second box. So connecting the power wire in box A to the light in Box A will turn on light A and same applies to Box B. The power in Box A and Box B are on the same fuse of course.
Old 12-07-14, 07:04 PM
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So........just wire the new switches like the old ones. Problem solved.

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