- Locate where the old transformer is located. Turn off or cut off power that’s feeding into your doorbell system. If you are not sure about the power line that’s feeding into the doorbell system, you can temporarily turn off the power in your house. Verify, check, and make sure that no electricity is running into the wires by using a multimeter or non-contact voltmeter.
- Remove the wires on the current transformer.
- Locate the junction box and take the cover off of the junction box. Again, verify that there is no power to prevent electrocution. Remove all of the wire nuts. Remember the color codes for the wires:
a. Black/Colored Wire – Neutral Wire
b. Green Wire – Ground Wire
c. White Wire – Hot circuit wire
- Remove the transformer from the junction box. Most transformers are mounted to the junction box via a plastic or metal nut. Loosen and remove the nut to remove the transformer. You can use a pair of pliers or screw driver to twist and remove the nut.
- Gently disconnect the wires (be careful not to strip the insulation).
- Mount the new transformer. Insert the wires and then reinsert the transformer bolt to mount the new transformer.
- Strip the new wires using a wire stripper. Strip around 3/8-1/2 of an inch.
- Wire each color wire to the wires on the junction box.
- Reattach the wire nuts and arrange the wires neatly inside the junction box. Attach the junction box cover.
- Rewire the doorbell wires on the new transformer.