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3-way switches - Oh not again!

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  • 3-way switches - Oh not again!

    We are trying to wire 3-way switches in our home. They worked fine, but we needed to replace the color of the plates and switches in this 35-year old house.

    I have read the discussion about 3-way switches, but I believe that this problem is different.

    We have 2 black wires and 1 red. The wiring boxes we bought have in one side one brash terminal, and in the other side, it has a brash and a brown terminal.

    We are just unable to find the right combination for the wires. The witches work, but only as a one-way switches. If we switch the light off from one of the 3-way switches, one needs to go back to the switch that was used to switch the light off to switch the light back on. shows a diagram for a 3-way switch that looks just like the ones we bought.

  • #2
    Re: 3-way switches - Oh not again!

    look here



    • #3
      Re: 3-way switches - Oh not again!

      Playing with power is inherently dangerous if you don't know anything about it. That said if you continue then you must have some basic skills. Basically you need to have the hot feed to the black (or brown) screw on one switch and the 'hot' wire for the light connected to the black screw on the other switch. You should have 3 wires in each box that go to the switches. Turn off the power and disconnect them all. Use a meter test them all for power (they should all be dead with the power off). Now that we know they are all dead measure the resistance of each wire to neutral. With a 60W bulb as the light that is connected one of the wires will measure about 240 ohms the rest should be open loop (infinite ohms or OL displayed on meter). Connect the wire that measures 240 ohms to the black screw on that switch. connect the other two wires from that box together and go to the other box with your meter. test the resistance between pairs of wires (3 choices) when you find the pair that measures 0 ohms tie them to the brass screws (does not matter which wire goes to what brass screw) The other wire is the hot feed that goes to the black screw. Go back to the box that you tied the two wires together and untie them, they go to the brass screws (does not matter which wire goes to what brass screw)


      • #4
        Re: 3-way switches - Oh not again!

        nice one wbrooks..
        clean and clear method.
        easy to understand.
        This should be archived somewhere ...
        Licensed Philadelphia electrician
        Philadelphia emergency lighting certification


        • #5
          Re: 3-way switches - Oh not again!

          Great idea wbrooks...

          Just make sure you don't have any device or light plugged in or turned on in the same circuit you are testing, or you won't get an open reading with the meter attached to the hot line. You can disconnect both switches and with the wires carefully separated turn the power on and check which one is hot.


          • #6
            Re: 3-way switches - Oh not again!

            WBrooks ;

            that trick i did rember that few time and yeah i done that when some of my comuster screw up the 3/4 way connections and i do the ohm test and that is very common way i done it and there are few older home used other oddball 3 way connections as well but i am not going into this because few oddball connections are illegal anyway

            merci , Marc


            • #7
              Re: 3-way switches - Oh not again!

              I wonder if Rosa's gonna come back and give an update. I sure hope she didn't zap herself!!


              • #8
                Re: 3-way switches - Oh not again!

                I did not see the notification untill today. I always reply to helpful information.

                This is what happen:

                My son happened to come to visit us and little did he know of the plans I had in mind. He did not seem to mind, and he was the right person for the job. He said no to get excited about the wire colors. He did 4 3-way switches - mainly following that diagram I uploaded last week - but I had not enough 3-way switches for the rest. This is what he did: He identified where the wires were coming from and advised to keep the 2 wires coming from a seath, each to one of the 2 top connectors, and the remaining wire to attach it to the bottom connector.

                He left, but a friend is coming next week to install the rest 3-way switches, and will follow my son's directions, so it should work.

                Thank you very much every one.


                • #9
                  Re: 3-way switches - Oh not again!


                  Thank you very much for the link to the diagrams. These are far better than others I've seen and will come handy when installing the rest of the 3-way switches. My daughter and I took some electrician courses a while back.


                  • #10
                    Re: 3-way switches - Oh not again!

                    W Brooks:

                    Thank you for the directions. They'll become very useful when we tackle the rest fo the 3-W switches.