Control/Dimming 3-way switch circuit trouble

[D Oz]

The work lights at my theater are all on a circuit together. They are controlled by a switch onstage and a switch in the booth. Recently, I replaced those two switches with heavy duty 3-way switches to ensure control from those two locations.

When I tested the switches, I discovered that the one onstage was acting as an enabler, such that the work lights would not turn on with a flip of the booth switch unless the onstage switch was "on" (so to speak).

I don't know what's going on here. I took pains to wire the switches correctly with the help of a multimeter. But I am no master of electrical theory. Please help!

One random fact that may prove relevant: the work light circuit also powers the lights in our electrical closet (which have their own switch). Perhaps the way the circuit is wired makes the 3-way switches act improperly?

 

[robartsd]

There are a variety of ways that 3-way switches might be wired. Check out http://www.homeimprovementweb.com/information/how-to/three-way-switch.htm, you may find something there that helps you figure out your theater's wiring.

 

[robartsd]

Also, the multiway switching article on wikipedia has diagrams that provide a good conceptual understanding of 3-way switching. The California 3-way listed there may be applicable.

 

[JD]

Two most common reasons for that symptom:
1) Common and one of the outputs are reversed on one of the switches.
2) Break in the wiring on one conductor between the two switches. (Check for wirenut slip if there is a junction in line)
Were there problems before the switch was changed?

 

[D Oz]

There are a variety of ways that 3-way switches might be wired. Check out http://www.homeimprovementweb.com/information/how-to/three-way-switch.htm, you may find something there that helps you figure out your theater's wiring.

Thanks, robartsd. Those diagrams helped me visualize the issue better. I was able to review my work, and just as JD suggested, it turned out that I had reversed the wire intended for common with one of the traveler wires. After switching them, the circuit and switches worked perfectly.

 

[derekleffew]

Glad you got it working, @D Oz. It's great to hear CB success stories. Don't feel bad, I screw it up just about every time I have to deal with 3way switches. Hate the things with a passion; there's just got to be a better way.

Fun fact: If you're ever tempted to use 3way dimmer switches, there's NO way one can wire them so one will not always be the master, and if it's down, the other won't work. Repeat, no way. I tried and tried for months in my hallway, and eventually gave up and put back in the switches, cursing every time I used them, as I've changed almost all the other wall switches in my house over to dimmers. Last year I put HUE lamps in the fixtures (one at each end) in the hallway. So now I have the convenience of having to drag out an iPhone, iPad, or laptop to turn lights on or off. But when's it's raining, the lights turn blue, and when I get a text, they flash red. Ah, progress.

 

[JD]

If you're ever tempted to use 3way dimmer switches, there's NO way one can wire them so one will not always be the master, and if it's down, the other won't work. Repeat, no way.

Maybe not off the shelf and maintaining it's UL approval, but where there's a will there's a way

 

[RickR]

There are several off the shelf dimmers that do 3 way. They are technically master & slave, but operate as full 3 way. Look at the 3 Ls; Lutron, Leviton and Lightolier.

 

[robartsd]

The simplest way to implement dimming in conjunction with 3-way switching would be to put the dimmer in series with the switching (either before the 3-way switches, or between the last switch and the load). This is what I've assumed the 3-way dimmer switches that have a toggle and a slider are doing - the slider controling a dimmer on the common side of the toggle. With this type of system, the dimmer itself would be a master - if it was too low to provide light, there would be nothing you could do at the remote switch to turn on the lights. I could see a master & slave setup allowing dimmer control from any switch location, but that would likely require all the switches to be connected to the hot and neutral to power their circuits - connections that may not be availible in the electrical box where existing 3-way switches are located.

 

[STEVETERRY]

Glad you got it working, @D Oz. It's great to hear CB success stories. Don't feel bad, I screw it up just about every time I have to deal with 3way switches. Hate the things with a passion; there's just got to be a better way.

Fun fact: If you're ever tempted to use 3way dimmer switches, there's NO way one can wire them so one will not always be the master, and if it's down, the other won't work. Repeat, no way. I tried and tried for months in my hallway, and eventually gave up and put back in the switches, cursing every time I used them, as I've changed almost all the other wall switches in my house over to dimmers. Last year I put HUE lamps in the fixtures (one at each end) in the hallway. So now I have the convenience of having to drag out an iPhone, iPad, or laptop to turn lights on or off. But when's it's raining, the lights turn blue, and when I get a text, they flash red. Ah, progress.

If you can find a Lightolier Onset Micro-Touch dimmer and an Onset Remote, they work really well in a multi-master 3-way setup. They can be retrofit onto standard 3-way switch wiring.

ST