How do I find my Doorbell System's Voltage?

This article describes how to locate transformer voltage for your existing doorbell chime system. The Video Doorbell requires 16 - 24 VAC at 50 - 60Hz, and 40VA maximum from mechanical or digital chime systems.

Note: Even when wired, the Video Doorbell is always powered by size AA, 1.5-volt, lithium non-rechargeable batteries.

Locating the transformer voltage for your doorbell chime system

Risk of electrical shock. Always use caution when handling electrical wiring.

Transformers always have their voltage and Volt-Amps (VA) printed on them. Sometimes this is called "max load" or "max power consumption rating," which is printed on the transformer. Transformer electrical information can be found in the following places:

  • On a label or sticker located on the outside of the chime system housing. 
  • Imprinted on the plastic mold of the chime system housing (may be difficult to locate).
  • On a label or sticker located inside the chime system housing.

Possible transformer locations include: 

  • Near the main electrical panel.
  • Inside the doorbell's chime box.
  • In the garage or attic.

Note: You may be able to follow the wiring from your chime to the transformer to locate the transformer.

Transformer information

What you need to know

The Video Doorbell is compatible with doorbell transformers that output 16-24 VAC with a maximum of 40VA.
Note: 16 VAC and 10 VA is the smallest recommended transformer to power the Video Doorbell.

In North America, most electrical circuits supply 120 volts. In the UK, and most of Europe, power circuits supply 240 volts. Both of these power options are too powerful for a doorbell. A doorbell transformer takes the standard electrical voltage in your home and lowers it to about 10 to 24 volts. This keeps the Video Doorbell powered at the right voltage for optimal operation. 


  • Volts of Alternating Current (VAC) - Refers to how much electrical energy can flow through the circuit. Volts may be listed as VAC, V, or Volt.
  • Volt-Amps (VA) - A transformer's VA rating shows the maximum energy it can produce. A direct current (DC) transformer normally shows power in watts.

Wiring your transformer

If you are able to select wiring for your transformer, we recommend running 18 – 22 American Wire Gauge (AWG) wire between the transformer and doorbell.

Example of a transformer


"Wired power not supported" error message

What does "Wired power not supported" mean?

If the power level for your existing chime system is not compatible, your doorbell will default to Event Response mode and the "Wired power not supported" alert displays during setup.

If your existing chime system is not compatible, you can add the Video Doorbell to a Sync Module system to enjoy features such as on-demand Live View, manual thumbnail images, and more.


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