Weird 3-way switches

10 years ago

We just bought a house with 3 way switches installed for the hall light and for the kitchen lights. Both of them behave as follows:

When you switch the 2nd switch to "on", the main switch works as normal - eg it turns the light off and on.

When you set the 2nd switch to "off", the main switch does nothing at all. The light just stays off.

This is a 60 year old house with the original ungrounded wiring everywhere but kitchen and bath receptacles.

Will a 3 way switch even work when wiring is not grounded?

Any clues/hints about what might be wrong here?

Thanks.

Sort by:Oldest

Comments (4)

User
10 years ago
The wires are switched to the wrong terminals on one or both switches.

Grounding has nothing to do with it.

Correct wiring:

Incorrect wiring:
randy427
10 years ago
If the switches have ON and OFF positions labeled, they are not 3-way switches.
Related Professionals
Albany General Contractors · Augusta General Contractors · Hattiesburg General Contractors · Murfreesboro General Contractors · Spring General Contractors · Lansing General Contractors · Helena General Contractors · Anchorage General Contractors · Brunswick Home Remodeling · Dalton Home Remodeling · Kansas City Home Remodeling · Murfreesboro Home Remodeling · Waterbury Home Remodeling · Bend Home Remodeling · Evansville Bathroom Remodelers
Pyewacket
Original Author
10 years ago
Yeah. They don't (have labeled positions), and they are (supposed to be) 3 way switches. Saying "on" and "off" in this case doesn't mean a particular switch position, it just means toggling it. Both sets of switches have specific positions that the one switch must be in for the other to work, but I didn't bother to write that down exactly.

I CAN, if you think that will help - but I'm pretty sure its not germane.

@Fred - I don't quite understand your schematics. I'm guessing the black lines represent the "hot" line - but what's the purple line? There are 2 traveler wires in addition to "hot" but I don't see where to attach those nor what wires coming out of the wall are supposed to go where.

What I do know about 3 way switches is the live wire is supposed to go to one place on the switch - I THINK that used to be labeled "common"? And then the 2 traveler wires go elsewhere. Elsewhere being a nebulous term that merely means I know they're supposed to be wired into the switch somewhere other than where the live wire goes.

I've read some stuff about how to determine which wire is which, but it requires turning the breaker back on so you have live wires and can test with a multimeter. Makes me nervous. I may have to do that anyway, given this is not a situation where you have a correctly wired switch and you're just replacing it.

Thanks.
User
10 years ago
In the schematic, the black wire on the left is the power source. The black and red wires between the switches are the travelers. The purple represents which two poles of the switch are connected together in relation to which way the switch is flipped at the time (the arrows represent which way the switch is flipped). You can follow the lines to see why the circuit is not always connected. There are two terminals on the switch that are the same color (travelers), and one of a different color (common). Common refers to the terminal that is common to the other two terminals. In the box, the two wires that are travelers will both come out of the same cable. That is often all you need to know to get the switch wired correctly. Sometimes, all three wires that attach to the switch come out of the same cable, which is when a volt meter may come in handy.
Pyewacket thanked User