Once that is complete, you’re free to follow the steps below for wiring the new transformer.
If there is an existing wired doorbell, then this makes the job a lot easier.
Locate the doorbell transformer before starting the project.
The Spruce / Kevin Norris
Use a voltage testerto check the transformer.
This is the best way to determine if the electricity is off.
Even if you are confident that the power is off, double-check the electrical system with a voltage tester.
Remove the Old Doorbell Transformer
Use a screwdriverto remove the transformer junction box cover.
Put the cover and the screws in a safe location for reinstallation.
After removing the wire nuts, untwist and separate the ends of the wires.
Next, use a screwdriver to unscrew and disconnect the low-voltage wires that connect the transformer to the doorbell.
If there are multiple doorbells, then there will be more than one set of low-voltage wires to disconnect.
Consider wrapping each set with electrical tape so you dont mix one set up with another.
Loosen the screws or bolts that are holding the transformer to the junction box, then remove the transformer.
Set the screws or bolts aside with the junction box cover.
The new transformer will also have a set of black, white, and green wires.
Twist the ends of two matching wires together, then cover the connection with a wire nut.
Next, reattach the low-voltage wires to the screw terminals on the transformer.
Turn On the Power and Test the Doorbell
Replace and secure the junction box cover.
Turn on the power at the electrical box, then test the doorbell.
Press the button and listen for the chime.
