How to Install a Doorbell

Doorbell on House

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Project Overview
  • Total Time: 1 - 3 hrs
  • Skill Level: Intermediate
  • Estimated Cost: $25 to $50

Your home's doorbell is the official greeter for everyone who stops by your house. So, if you want the doorbell to be as dependable and solid as possible, a wired doorbell (in contrast to a wireless doorbell) is a good choice.

Wired doorbells never need their batteries changed. Because they use household 120V electricity stepped down to a 16-volt operating current via a transformer, they're able to deliver a strong current to the chimes for a ring that's easy to hear. Plus, if you'd like a doorbell that's lit and easy to see even in the dark, this feature is available with wired doorbells.

A wired doorbell is a perfect—and permanent—complement to a house.

Before You Begin

If you are replacing a wired doorbell, keep the existing wire in place when you remove the button. In many cases, the wire should still be in good shape for reuse. More importantly, reusing the doorbell wire eliminates the need to fish new wire through the walls.

Purchase the four major wired doorbell components separately—button, wire, transformer, and base—or purchase a kit that includes everything that you need. Note that one advantage of buying a wired doorbell kit is that you can be confident that all of the materials are compatible.

How Wired Doorbells Work

The main elements of a wired doorbell system work in conjunction, a process that starts when a visitor presses the doorbell button.

Doorbell Button

The wired doorbell button is located to the left or right of the front door.

Behind the doorbell button is a hole. Two separate strands of doorbell wire feed through the hole and are attached to the back of the doorbell button at two terminals. One wire leads to the doorbell transformer and the other wire leads to the doorbell base (chimes).

Doorbell Wire

The doorbell wire, or bell wire, is thin, 20/2 coated copper wire. It has two strands, often with one strand coated in white plastic and the other strand is coated in red plastic. The strands are separated into single strands for this project.

Doorbell Transformer

The doorbell transformer is a solid-state electrical device that attaches to the side of an electrical box.

The transformer converts the higher 120V household current input to a lower 16V output that's usable by the doorbell system. The doorbell system cannot use 120V household current directly; it needs to be reduced or stepped down to a lower voltage.

Two electrical terminals are located on the back of the transformer. One doorbell wire from the doorbell button leads to the transformer. A separate wire leads from the transformer to the doorbell base.

Doorbell Base or Chimes

The doorbell base contains the chimes. On back are three terminals, often in this order:

  • REAR: REAR refers to a back doorbell. This terminal leads to an optional second doorbell at the back of the house. As this project is about wiring a front doorbell only, ignore this terminal. It will not be used.
  • TRANS: TRANS means "transformer." A single strand bell wire leads from this terminal to the doorbell transformer.
  • FRONT: FRONT refers to the front doorbell. A single strand bell wire leads from this terminal to one of the terminals on back of the doorbell button.

Electrical Box

The electrical box is a metal, enclosed box that has a 120V electric cable running into it. The box might be dedicated solely to powering the doorbell transformer or it might have another device such as an outlet running from it (though these other devices need to be mounted on separate boxes).

The box should have available knockouts that can be opened up to allow the transformer to be attached.

Safety Considerations

Exercise caution when wiring the transformer to the electrical box, since the box contains household current sufficient to cause injury or death. Work on the electrical box only when the circuit breaker to the box has been shut off. Use a non-contact voltage tester to make sure that power is off before working on electrical wires.

What You'll Need

Equipment / Tools

  • Cordless drill
  • Drill bits and drivers
  • Flathead screwdriver
  • Phillips head screwdriver
  • Wire stripper
  • Pliers
  • Voltage tester


  • Doorbell button
  • 50 feet 20/2 coated copper wire
  • Doorbell transformer
  • Doorbell base (chimes)
  • Plastic wire connectors


  1. Plan Layout

    • Doorbell: Install the doorbell next to the front door. The button should be around 42 to 56 inches high.
    • Transformer: Install the transformer against an available electrical box. Often, doorbell transformers are located near the electric service panel.
    • Doorbell Base: Install the doorbell base in a central location where the chimes will be heard in all parts of the house. The base will be surface-mounted.
  2. Install Transformer

    With the electricity turned off at the service panel, knock out one of the protective covers from a hole on the side of the electrical box.

    Attach the transformer to this hole by feeding the three wires in first, followed by the threaded section of the transformer. Turn the locknut on the inside of the electrical box to tighten the transformer to the box.


    Remove a knockout in a metal electrical box by tapping it firmly with a screwdriver until it loosens. When one side of the knockout is free, twist it several times by hand or with the pliers to fully detach the rest of the knockout.

  3. Wire Transformer to Electrical Box

    Attach the three transformer wires to the three 12- or 14-gauge wires that are already in the box. Attach the white wire to the white wire; black wire to the black wire; and green wire to either the green or bare copper wire. Twist the wires clockwise and follow by capping them with plastic wire connectors.

    Screw the faceplate or device with cover back onto the electrical box.

  4. Attach Doorbell Base Wire to Transformer

    Screw a single strand of bell wire onto either of the two terminals on the back of the transformer.

  5. Run Wire From Transformer to Doorbell Base

    Fish the single strand of bell wire from the transformer to the location of the doorbell base.

  6. Attach Transformer Wire to Doorbell Base

    Attach the wire from the transformer to the TRANS terminal on the back of the doorbell base.

  7. Run Transformer Wire to Doorbell Button

    Attach a second wire to the back of the transformer on its remaining terminal. Fish this wire to the location of the doorbell button.

  8. Attach Transformer Wire to Doorbell Button

    Attach the wire from the transformer to either of the two terminals on the back of the doorbell button.

  9. Attach Wire From Doorbell Base to Doorbell Button

    Attach a single strand of bell wire on the back of the doorbell base onto the FRONT terminal. Fish this strand to the doorbell location.

  10. Attach Doorbell Base Wire to Doorbell Button

    Fish the doorbell base wire to the location of the doorbell. Attach it to the remaining terminal on the back of the doorbell.

    With both wires attached to the back of the base, mount the base on the wall. Attach the decorative face by snapping it into place.

  11. Mount Doorbell Button

    With the cordless drill, first drill two pilot holes for the doorbell button. Next, turn the two included screws clockwise to mount the button to the doorframe.

Doorbell Wiring Map Summary

From To
Transformer, either terminal Doorbell button, either terminal
Transformer, either terminal Base, TRANS terminal
Base, FRONT terminal Doorbell button, either terminal
Base, REAR terminal Do not use. Not applicable for front door-only installations
Each connection uses one single-strand 20-gauge wire (or as indicated with your transformer)

Troubleshooting: Wired Doorbell Does Not Sound

Check Doorbell Button

The problem might be with the button itself. Depressing the button may not properly close the electrical circuit. Remove the doorbell button. Detach the wires from the button.

Holding the coated section of the wires, touch the bare ends together. If the doorbell rings, the button is at fault. Replace the button with a new one.

Check Doorbell Base

Remove the cover from the base. Make sure that the wires are attached to the terminals and are secure. With a multimeter, determine whether electricity is flowing through the wires.

Alternatively, remove the TRANS wire and touch it to the FRONT terminal while a helper pushes the doorbell button. Hold only the coated sections of the wire. You should see a small spark if electricity is properly flowing.

When to Call a Professional

Attaching the doorbell transformer to an existing electrical box and wiring it can be done by most do-it-yourselfers with basic electrical skills. Since the box contains full household current, though, you may feel more comfortable with hiring a qualified, licensed electrician to make this connection.

If there is not an available electrical box, an electrician can install one for you by feeding off of a nearby power source or by running a new circuit from the electric service panel.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Basic Electricity Safety. Occupational Safety and Health Administration.