Light Switch Wiring

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Old 09-01-17, 09:54 AM
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Question Light Switch Wiring

Need a little help figuring out a circuit.

I recently swapped out toggle switches for some hallway lights. To the best of my knowledge the circuit consists of:

Two lights in the ceiling
A 3-way toggle switch at one end of the hallway
A 3-way toggle switch at the other end of the hallway
A 4-way toggle switch in the center of the hallway.

Before I swapped out the switches you could turn on/off the lights at the same time from any switch and in any combination (e.g. turn on from one end of the hallway and turn off at the other)

Now, it seems to depend on which switch you turned the lights on from for instance you could turn them on from the middle, turn them off from one end but not turn them on from the other end. I haven't figured out a consistent pattern to the on/off combination.

Any ideas what to check for or fix much appreciated.
 
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Old 09-01-17, 10:11 AM
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Every three way switch has a common terminal. It was hard to see on very old switches. It could be black or just darker than the other two.

When you replace three way switches.... the wire that comes off the common screw must go back on the new switch common. There is no top or bottom or left side and right side.

With 4way switches you need to follow the diagram on the package it came in. Some switches have one pair of wires on the right and the other pair on the left. While others have one pair on the top and the other on the bottom.
 
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Old 09-01-17, 10:23 AM
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So Pete what you're saying is that even though it may look like I wired everything on the new switches exactly like it looked on the old switches (they were 50 years old) it is likely not because the posts on the old switches were probably different than the new ones..
 
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Old 09-01-17, 10:29 AM
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Yes... that is correct. One miswired switch will mess up the entire system.

If you have no idea now which one should have been common..... pull the device(s) out of the wall without removing the wiring. Follow the wiring. The two travelers will both go into the same jacketed cable. The odd wire left is the common.

If the switch is on the end of a 3 wire cable..... the travelers will be the same colors that are used on the 4way switch. The odd color is the common.
 
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Old 09-07-17, 07:32 AM
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I haven't looked at it again yet but I know from the swap that the 3-ways have r/b/w wire cables to them. The 4 way has two b/w cables going to it. When I looked at swapping out the two ceiling lights in that circuit one light had a rats nest of wires, including the r/b/w cable, all tied together in it's box. I didn't look at the other light but I assume the one I looked at is probably where the whole thing is tied together.
 
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Old 09-07-17, 01:28 PM
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All the splices in the one light box. That would be a homeowner installation.
It also makes for way too many wires to be located in one box.

That would mean....
2) three wire cables for the 3w switches.
2) two wire cables for the 4w switch.
1) two wire feed in
1) two wire out to second light.

You need to focus on the 2)three wire cables. Two of the wires from one should be connected to two wires of the other one. These are the travelers. The third wire will be the common.
 
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