Wiring Diagrams for Doorbells

–Check local regulations for restrictions and permit requirements before beginning electrical work–

–Most wiring diagrams on this site include a green dot representing the integrated grounding terminal found in most metal outlet boxes. However, some older metal boxes and most plastic boxes don't have a terminal like this.
–By code, the number of conductors allowed in a box are limited depending on its size. Conductors include wires, devices like switches and receptacles, and some other metal parts. Check here to calculate the number of conductors allowed in a box before adding new wiring, etc.

If you’re installing a new doorbell, a remote controlled device makes for the simplest installation and doesn’t require any of the circuitry illustrated on this page. All that’s required is to mount the button near an exterior door and the chimes in a convenient, central location inside the house. No need to run wires or splice into household circuits, fresh batteries are all that’s required.

If, however, you’re putting in a new hardwired doorbell or you need to repair an existing one, the diagrams on this page illustrate the most common installations you will find. Included are wiring for a typical hardwired doorbell, a two-button doorbell, an old house doorbell powered by a battery, and an alternate power source using an ac adapter.

Doorbell Wiring Diagram

wiring diagram for a hardwired doorbell

A hardwired doorbell includes a small transformer that converts the household alternating current (AC), to direct current (DC) for the doorbell chimes. A small, 16 awg wire runs from the door button to the chimes. When pressed, the button will send the transformer output through the chimes, sounding the bell until it is released.

Wiring a Doorbell for Two Doors

wiring for a doorbell with two buttons

A doorbell circuit for two or more doors will have a separate contact on the chimes for each button included. At the chimes, one wire from each button is spliced to the output wire on the transformer. The second wire is connected to one of the contact screws on the chimes.

Old House Doorbell Wiring Diagram

wiring for an old doorbell with battery power

It’s not unusual for an old house to have an old doorbell lurking about somewhere that hasn’t worked in years. Fortunately, it’s likely a simple matter to get things back in working order. As illustrated in the above diagram, the parts of an old doorbell circuit include the bell, a button mounted at the door, and a battery somewhere in between the two.

The battery is the weakest link here and should be the first place to look for trouble. The battery can be replaced with a large flashlight-type dry cell rated at 12 to 16 volts and if the wires are still intact and the contacts clean, the doorbell should come back to life.

AC Adapter Doorbell Wiring

wiring ac adapter to doorbell

Another, more permanent, repair for an old doorbell circuit is to use a small ac adapter in place of the battery. Most people will have an AC adapter left after an old radio or similar device has long since died. Look for an output of 10 to 16 volts printed on the side of the adapter casing. Current ratings will typically be very low from these adapters, around 500mA, making them perfect to power the doorbell circuit. All that is needed is a conveniently located receptacle to plug the adapter in.