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Need help with wiring 3 way switch

2K views 1 reply 2 participants last post by  HooKooDooKu 
#1 ·
I have two 3-way switches controlling 2 ceiling lights. Last night the 50W halogen bulb on a transformer burned out, and the incandescent flood would not turn off. So I unscrewed the light bulb and went to bed.

This morning I removed the transformer and replaced it with a housing for another incandescent flood. Both floods came on and would not turn off by pressing either switch. (The second switch is in a bank of switches, and I don't know which one controls the light, but none of the switches in the bank worked.)

My problem: The existing switch is a Lightolier ZP600VA dimmer with four wires: black, white, red, and yellow. Those wires are connected to black, white, black, and yellow wires respectively.

All new replacement 3-way switches have three wires. So am I heading in the right direction by assuming it's a bad switch? And how to I handle four wires in the wall with three wires on the switch?

Any help would be appreciated.

Jim
 
#2 ·
And how to I handle four wires in the wall with three wires on the switch?
Standard 3-way switches work using three wires by providing two alternate paths to ground.

As best as I can tell, dimmers and electronic 3 way switches with 4 wires work like this...
The black wire is the basic unswitched "hot" providing power to the electronic switch.
The white wire is the basic neutral wire.
The red is the switched power that provides the power to the load.
The yellow is a "signal" wire connected to a remote switch.

The way you make such a switch a 3-way switch is you run the neutral and the yellow wire to a "remote" switch. When you activate the remote switch, basically a signal is sent to the yellow wire telling it to turn the light on if it is off and off if it is on.


That's different from a hard-wired 3-way switch. In a hard-wired 3-way switch, you send a black and white wire to the 1st switch (constant "hot" and neutral). You connect the "hot" to the common of the switch, the black to one of the other two terminals and the red to the third terminal, and the white wire to the white wire. At the other 3-way switch, you use a black and white wire to send switched power to a light. The white connect to the white, and the black is connected to the common of the 3-way switch. The other two terminals of the 3-way switch are connected to the black and red from the other switch. In this setup. the hot travels through either the red or black switch, with each time you flip the switch, the common gets connected to the black or the red. When both 3-ways switches are connected to the red or both 3-way switches are connected to the black, the light lights up.

When electronic devices are used, the black and white wires are the power to the device, the red is the "hot" for the lights controlled by the device, and other wires (such as the yellow) are for remote signalling.

Of course a green wire should also be present, if so then it's connected to ground (bare copper wire).
 
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