Doorbell Wires


Old 08-07-20, 02:12 PM
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Doorbell Wires

Hi, I searched the forums but couldn't find what I was looking for. I have three exposed wires coming from my wall. I am trying to identify which one is the transformer wire. I have a voltage meter but I am stupid and don't know how to test each wire.

Do I need to get my wife to push the doorbell button whilst I check one of the wires, or do I need to combine two wires together and then have her press the button? I am looking for 16-24V on the meter correct?
Old 08-07-20, 03:13 PM
Tolyn Ironhand's Avatar
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You will likely need a helper or some say to press/hold down the button. With the front button held down, you should read 16-24 volts AC between two wires. Then press the other (back) button down and you should read the same voltage between two wires. The wire that was the same on both tests is the "trans" wire. The other two wires will coincide with whichever button was pressed.

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