Interactive diagram + guide

Doorbell wiring diagram

Press the buttons on the diagram to ring the chime and follow the low-voltage circuit from the transformer. Installing a video doorbell? Check your transformer first.

Installing a Ring or Nest video doorbell? Check your transformer first.

Tool
Interactive doorbell wiring diagramThree steps: pick your setup, flip the switches, wire it

Step 1 of 3

Which setup do you have?

Look in the box with the breaker off: what matters is where the power cable comes in. Pick the one that matches, or keep the one already selected.

Step 2 of 3

Press the buttons

Tap a switch, button or GFCI on the diagram. Glowing wires are carrying power right now. On a small screen, scroll the diagram sideways.

Doorbell Wiring With One Button wiring diagramTransformerChimeFront doorbell wirebell wireredwhiteredwhiteTransformerLVlow-voltage screw 1LVlow-voltage screw 2ChimeFront off · Rear offFRONTFRONT screwTRANSTRANS screwREARREAR screwFront buttonreleased1screw 12screw 2wire nut: bell wire splice
  • Black: hot
  • White: neutral
  • Red: hot / traveler
  • White + black tape: hot
  • Bare copper: ground
  • Wire nut
  • Glow: carrying power now
This is low voltage (typically 10–24 V), but the transformer’s other side is 120 V. Turn off its breaker before touching it.

Step 3 of 3

Wire it box by box

Safety first. Turn off the breaker and confirm the power is off with a non-contact voltage tester before touching any wire. Follow your local electrical code; some areas require a licensed electrician or a permit. If you find aluminum wiring, cloth-covered wiring, scorched insulation or more than one circuit in a box, stop and call an electrician.

Transformer

Chime

Front door

Guide

How a wired doorbell works

A transformer turns 120 V into low voltage, typically 10, 16 or 24 V AC. One transformer wire goes to the chime’s TRANS screw. The other goes to the doorbell buttons, and each button returns to the chime’s FRONT or REAR screw. Pressing a button completes the circuit and a plunger strikes the chime.

Where is the transformer?

Look near the breaker panel, on a junction box by the furnace, in the attic, a closet or the garage, and sometimes inside the chime. Its voltage and VA rating are printed on it.

Upgrading to a video doorbell

Video doorbells replace the button and use the same two wires, but they need more power than a plain button. Use the video doorbell transformer checker before you buy.

All doorbell setups

What you need

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Frequently asked questions

What voltage is a doorbell transformer?

Most are 10, 16 or 24 V AC. Many video doorbells need 16–24 V, so older 10 V transformers often need an upgrade.

Does it matter which wire goes on which doorbell button screw?

No. A plain doorbell button is a simple switch with interchangeable screws.

Why doesn’t my doorbell work?

Check the button first by touching its two wires together briefly (it’s low voltage). If the chime rings, replace the button. If not, check the transformer’s output and the chime’s plunger.

Is doorbell wiring dangerous?

The button and chime wiring is low voltage, but the transformer’s primary side is 120 V. Turn off its breaker before working on the transformer.

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