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How to Replace a Doorbell

Master electrician Heath Eastman helps a homeowner solve an old problem: locating and replacing doorbell components and wiring.

Master electrician Heath Eastman takes us on a house call to solve a homeowner’s doorbell problem. After moving in, the homeowner attempted to fix an old doorbell, only to have it crumble into pieces. Heath uses his expertise to track down the existing wiring and transformer first before running new wiring and installing a new doorbell, chime, and transformer.

Doorbell Replacements Can Be Complicated

On the surface, replacing a doorbell might seem like a simple proposition. However, locating all of the components (inside the wall and out) can be more complicated than that. Here are the components to find:

  • The transformer: This is a square block typically located near the electrical panel, in a closet near the front door, or in the basement mounted to a joist under the front door.
  • The chime: This is the box that makes noise when someone presses the doorbell. It’s usually located above the front door.
  • The doorbell: Mounted outside the front door.

Once you locate these items, the job may move forward quickly. If not, there’s more work to be done. This guide will explain the latter.

How To Replace a Doorbell

  1. Start by locating the transformer and the door chime. These items may be buried or hidden if they are not easily found. If that’s the case, remove the doorbell button from the outside of the house and remove the wires. Clip a wire toner to the wires and trace the sound through the home to locate them.
  2. Use a magnetic stud finder to locate the studs around the wire. They should be running through an open stud bay, and this stud finder will help paint a clearer picture.
  3. Cut a small hole where the new chime will be located. Fish for the doorbell wires behind the wall and pull them out. Note: These wires are much thinner than typical house wiring.
  4. Use a meter to test if they’re doorbell wires by placing the meter in continuity mode, holding the leads on the wires, and touching the doorbell’s wires together. If the meter beeps upon touching the wires, it’s the doorbell wire.
  5. If the old wire is rough, tape the new wire onto the end of the existing doorbell wire, wrapping the wires together in the process. Carefully attempt to pull the old doorbell wire through the wall, pulling the new wire in to replace it. If the wire won’t budge or breaks in the process, use fish tape fed from one side of the wall, through the stud bay, and out to the other side to grab the new wire and pull it back through. Leave a foot or two of wire on both sides of the wall.
  6. In the basement, find the joist bay directly underneath the stud bay above. Drill a hole up through the basement ceiling and into the joist bay above. Run the fish tape up through the wall and back to the hole behind the chime. Tape a wire to the end of the fish tape and pull it back through, pulling enough to reach the new transformer’s location.
  7. Place the doorbell chime on the wall, covering the hole. Use a level to get the proper orientation before marking the mounting hole locations on the wall. Remove the chime, drill the mounting holes, and install the anchors with a hammer. Feed the wires through the chime and then attach the chime to the wall. Attach the transformer wire to the transformer terminal and the doorbell wire to the doorbell terminal before covering the chime.
  8. Strip the jacket back on the wire running to the doorbell. Strip each wire back about ½-inch and wire them according to the manufacturer’s directions. Place the doorbell button over the hole so that it’s blocking it completely before screwing the doorbell to the outside of the house.
  9. The new transformer will likely mount to the side of the electrical panel. Homeowners who aren’t comfortable working within their electrical panel should call an electrician for this part of the project, and they’ll attach the wires to the new transformer. Otherwise, shut off the power to the electrical panel at the main breaker and remove the cover. Choose a knockout on the side of the electrical panel and knock it out with the wire strippers and a screwdriver. Slide the transformer’s threaded end into the panel and secure it with the locking nut.
  10. Run a small length of wire from the original doorbell’s 15-amp breaker to the transformer. Attach the wire running from the chime to the transformer before closing up the panel, flipping the breakers back on one by one, and testing the new door chime.


Heath installs a doorbell using the old doorbell wiring. The previous homeowners disabled the doorbell and buried the old chime location in the wall.

Heath uses a tone generator to find the location of the old wiring. After confirming there is doorbell wiring behind the front hall walls, Heath uses a magnetic stud finder to confirm the location of the studs. Knowing where the studs are tells Heath where the bay in the wall is, so he can run wire to the chime.

After deciding where the chime will go, Heath uses a box cutter to cut a square opening to feed the wire through the wall. Using electric fish tape, he can run the thermostat wire to the chime and the basement. To connect the power, Heath installs a new transformer in the basement near the electrical panel.