Procedure for wiring three way switch?

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Old 02-04-19, 09:07 AM
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Procedure for wiring three way switch?

We were replacing the old three way switches in our bathroom and cut off the old wires without noting which one went to the black screw. The switches control some lights which appear to be located between the two switches. One receptacle has two black and one red wire and the other receptacle has a black, white and red wires. Both receptacles have ground.

How can I determine the correct wire to attach to the two black screws on the switch? Is it true it doesnt matter which of the other two wires are hooked to the two brass screws?

Thanks in advance for any help!
 
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Old 02-04-19, 09:22 AM
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You're talking about switches and receptacles

Are you referring to the wiring at the three way switches ?
If yes..... the one with red, white and black........ the common is white.

At the end with two blacks and a red.... the common will be black. Look at the three wires. The two traveler wires will go into one cable with a white wire. The remaining black is the common.
 
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Old 02-04-19, 11:49 AM
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The three way with the two blacks and the red. Put the black and red from the same cable on the traveller screws(the not black screws). The lone black on the common screw(black screw). Just to confirm there should also be two whites connected to each other the box.

The other end is pure guess unless you open the light, but it should take three tries most to get it correct. The common screw is the only one the matters and there are only three wires to try on. Put the black wire on the common and try the switches. If they don't function properly try the red. Try the white last.
 
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Old 02-04-19, 11:59 AM
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If the red and blacks are travelers at end A..... it stands to reason that red and black are travelers at the B end. That leaves white as the common.
 
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Old 02-04-19, 12:32 PM
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Thank you for the advice.

I wired the switches as specified in pjmaxx's first response and it does not seem to work properly. If we call the switch with two black and one red Switch A, then when the top toggle is depressed inward (Leviton switch), the lights come on but only if the bottom toggle on Switch B is depressed. In this configuration, both A and B turn the lights on and off from their respective switches. If the top toggle on A is depressed as above, one can now turn off the lights at B, but , oncethe lights are turned off at B, A cannot turn on the lights.

Is it possible to measure which wires are which by measuring the continuity through light fixture or from switch to switch?
 
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Old 02-04-19, 02:01 PM
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If you have a voltmeter.... measure to neutral or ground..... one wire at one end will be hot. That is a common connection. The two remaining wires will be the travelers. After you wire this switch..... go to the opposite end. One wire will be hot when the switch is in one position. This will be a traveler. Flip the switch the other way. Find the other hot wire. This is the other traveler. The remaining wire is the common.
 
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Old 02-04-19, 02:17 PM
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The single black is common. Just keep trying different ones on the other common until it works.
 
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