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Hi guys. I have a frustrating problem. I am replacing a lot of the 3 way light switches in my 1964 house. All of my problems are in rooms wired with 2 switches for one fixture. The problem I'm having is that some lights can be activated by only one of the 2 switches in a room only, or sometimes you can turn the light on with one switch and off with the other only. All I'm trying to do is make each room work so that the light can be turned on or off by either switch. The wire coming into most of the switch boxes are red, white, and black, with bare copper grounds. (and yes, I'm installing new 3 way switches to replace old 3 way switches)Is there an easy way to figure out what's wrong with the wiring? Thanks so much.
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Three way swiches are a bit different in that they have a dark colored screw called the COMMON screw. The other two screws are for the TRAVELLERS. Before you ever replace any of these type of swiches you first need to lable the wire that is attached to the COMMON screw. The reason for this is cause the COMMON screw is not always in the same location for every switch.
Here's a link that'll explain to you how 3-way switches work:
Now, in order to fix your wiring the right way the first time, you'll need a multimeter. This way you can test for both voltage and continuity (ohms) with the same instrument. You can buy an analog type meter at Radio Shack for around $10.00 and up, plus you'll use it lots for other projects.
On the three way switch, there are three screws. They should be different colors. Two are the same (usually a brass color), and one is different (usually black). The black screw is known as the common and depending on the position of the switch, the common is making contact with either of the two brass colored screws, which are the travellers.
This will work if the hot line-in feed from the panel comes into a switch box.
Open the breaker for this circuit.
Remove all wires from both switches and spread them out so they’re not touching anything or each other.
Close the circuit breaker.
Using your voltage tester, measure each wire individually to ground to find the wire that is supplying 120V. Once found, this is your Common wire. Mark it as so.
Open the circuit breaker again.
Unscrew the lamp from it’s socket.
In the switch box that contains the common wire you just identified, temporarily twist the two traveller wires bare ends together.
Now go over to the other 3-way switch box, and using an ohm meter or tester that will indicate continuity, locate the two wires that show continuity.
These two wires will be the travellers.
The remaining wire will be your other Common wire. Mark it as so and connect it to the dark screw on the switch.
Connect all remaining wires to the appropriate screws on both switches.
Screw in the lamp to it’s socket.
Close the circuit breaker. -
Perfect. Thanks!!!
quote:Originally posted by kactuskid
Three way swiches are a bit different in that they have a dark colored screw called the COMMON screw. The other two screws are for the TRAVELLERS. Before you ever replace any of these type of swiches you first need to lable the wire that is attached to the COMMON screw. The reason for this is cause the COMMON screw is not always in the same location for every switch.
Here's a link that'll explain to you how 3-way switches work:
Now, in order to fix your wiring the right way the first time, you'll need a multimeter. This way you can test for both voltage and continuity (ohms) with the same instrument. You can buy an analog type meter at Radio Shack for around $10.00 and up, plus you'll use it lots for other projects.
On the three way switch, there are three screws. They should be different colors. Two are the same (usually a brass color), and one is different (usually black). The black screw is known as the common and depending on the position of the switch, the common is making contact with either of the two brass colored screws, which are the travellers.
This will work if the hot line-in feed from the panel comes into a switch box.
Open the breaker for this circuit.
Remove all wires from both switches and spread them out so they’re not touching anything or each other.
Close the circuit breaker.
Using your voltage tester, measure each wire individually to ground to find the wire that is supplying 120V. Once found, this is your Common wire. Mark it as so.
Open the circuit breaker again.
Unscrew the lamp from it’s socket.
In the switch box that contains the common wire you just identified, temporarily twist the two traveller wires bare ends together.
Now go over to the other 3-way switch box, and using an ohm meter or tester that will indicate continuity, locate the two wires that show continuity.
These two wires will be the travellers.
The remaining wire will be your other Common wire. Mark it as so and connect it to the dark screw on the switch.
Connect all remaining wires to the appropriate screws on both switches.
Screw in the lamp to it’s socket.
Close the circuit breaker.Comment
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