Replacing old switches in a 1950's house

I'm in the process of replacing a bunch of light switches in my house because several of them cause the lights to flicker if you wiggle the switches around, and some seem really loose and worn when flipping on and off. I was expecting to deal with just two and three- pole switches, then I came across this setup that's a bit confusing.

The right switch of the pair in the wall, and the switch by itself will turn a kitchen light on and off. You can have either of the switches in any position and make the light turn on/off with the other switch. They are also not labeled on/off on the switches. On the switch by itself, the screw on the top right was removed. There's also a flood light outside that doesn't work, and I kind of wonder if it's wired to one of these switches as well. Can anyone help explain what's going on with this wiring? Any help's appreciated.

I coukd give a better answer if yiu removed the tape from the switches.

The pair of switches that control the kitchen lights are 3 way switches. You would need to buy 2 new three way switches. The new ones will have one black screw (the common), and two brass screws ( the travelers). You would hook the incoming power black wire to the common screw of one switch, and the black wire that runs to the light fixture to the common screw of the other switch. The travelers would be hooked to the brass screws at both locations, and it doesn't matter which wire is connected to which screw.

Are there any wires back stabbed into any of the switches? If a screw is missing, is there a wire that is not connected to anything?

When I removed the tape from the one switch in pic #2, it showed a red and black wire connected to the brass screws and another black wire connected to the black screw. All wires are connected.

The only thing now that's throwing me off is that the ground wire is connected to the black screw on the switch by itself. I've never seen this before

Jimmyo said:

When I removed the tape from the one switch in pic #2, it showed a red and black wire connected to the brass screws and another black wire connected to the black screw. All wires are connected.

The only thing now that's throwing me off is that the ground wire is connected to the black screw on the switch by itself. I've never seen this before

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What color is the wire that you are calling the "ground wire"? What makes you think it is a ground wire?

Again, pictures, with the tape removed, and the wires cleaned off would make it far easier to diagnose.

Also, which switch has the missing screw?

I was about to start in but Jeff is right! Guessing on my part does you no good at all and could even get your and/or yours hurt. Pictures and the answers to Jeff's questions and we'll be able to help.

"I was expecting to deal with just two and three- pole switches, then I came across this setup that's a bit confusing."

The one thing I would highly suggest that you do first is to get your terminology correct so that you can follow us when we give you directions and instructions and also when you read up on the internet about these types of switches that are in your home.

The switches in your home are not as you state "two and three- pole switches". These types of switches are totally different than what are in your home and that you are referring to. The ones in a typical home are "single pole", "3-way" and "4-way" switches.

You can take a look HERE and read up a bit on how they operate and when they are used. This will help you understand them better and also help you when we give you instructions and assist you in analyzing your wiring layout.

At the risk of being pedantic I must point out that single switches are "single pole, single throw"; 3 way switches are "single pole, double throw"; and that 4 way switches are "double pole, double throw."

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Tom Horne

Sorry, lol. I meant single and 3-way. I'm referring to the bare copper wire as the ground. The switch that's by itself is the one with a screw missing

The additional pictures are very helpful. As I feared some ignoramus has used an Equipment Grounding Conductor (EGC), from one of the cable runs, as a current carrying conductor. That is a forbidden practice under the US National Electrical Code (NEC). Since that conductor is not insulated I wonder how they managed to avoid a ground fault already. But if the EGC is being used for a current carrying conductor that box may be completely ungrounded. In American parlance that means that there may be no return pathway back to the utility transformer for a fault that connects the metal box enclosing the switches to a current carrying conductor. That means that the entire box, any face plate mounted on that box, and any other conductive object that has a conductive path to that box could become energized and stay that way until someone comes in contact with it and receives a shock. If that happens only factors that have occurred by chance will affect whether the shock is surprising, unpleasant, painful, or deadly.

First apply a non contact voltage tester to the short slot of a working receptacle outlet. Then apply the non contact voltage tester to the box in question and each conductor. If the box itself tests as energized stop right there. If the box does not cause an indication from the non contact voltage tester you can then test the wires. The only safe way to test for the possibility that the box is ungrounded is with a solenoid voltage tester; which is often called a Wiggy after it's inventor George P. Wigginton. A Wiggy is an electromagnetic voltage tester. When connected to 2 conductors that have a difference in voltage which approaches of surpasses 120 volts a Wiggy will vibrate and draw ~0.007 Amperes or 7 milliamperes. That is not enough current to cause arcing or kindle a fire in a defective circuit but it is enough to rule out minor capacitive effect voltage from an adjacent energized conductor. Both a volt ohm meter and a neon light tester can give a false voltage reading from the voltage which couples into the conductor under test from a parallel conductor. This coupling effect cannot provide the 7 milliamperes it takes to get a voltage reading from a Wiggy. With the circuit energized test that bare conductor against each of the other conductors in the box and against the box itself. When testing to the box place the probe in contact with the screw threads of the holes which except the device mounting screws. That will avoid any enamel or paint from preventing contact with the metal of the box. If none of the conductors cause the Wiggy to vibrate you will need to run an extension cord from a receptacle outlet that does show voltage when testing between the short slot and the round opening for the "Ground Pin." Once you have run that cord to the box you will use the round opening on the cord's receptacle for one probe and the other probe to each wire in the box in question. If one of those wires causes the Wiggy to vibrate and the solenoid pointer to move to around 120 volts then retest between that wire and the box. If you still get no voltage indication between an energized conductor and the box the EGC to that box is either open or never existed. That is a seriously dangerous condition. At that point you may have to call in a professional electrician to sort out the problem.

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Tom Horne

hornetd said:

At the risk of being pedantic I must point out that single switches are "single pole, single throw"; 3 way switches are "single pole, double throw"; and that 4 way switches are "double pole, double throw."

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Tom Horne

Click to expand...

...and the 4-way also has an internal crossover in it, and has only 4 connections, rather than 6, so it's not a "pure" DPDT.