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Doorbell Wiring Diagrams

From past to present the common 2-note door chime has remained a simple wiring configuration. The provided wiring diagrams are based on the NuTone 2-note door chime but the common wiring layout should pertain to all other brands of chimes as well.

Wiring too difficult? Try a wireless doorbell

**Consult your specific brand of chime for further reference.

Nutone 2 Note Door Chime

Common NuTone Door Chime FAQ

  • Can a two-note chime be replaced by a 4- or 8-note chime?
  • May two-chimes be on the same pushbutton?
  • What can be done for a two (2) note chime that does not ring loud enough?
  • If an application is to connect two, 2 note chimes together, will 2 transformers be required?
  • What is occurring if the chime rings by itself?

Find many more common questions and answers at NuTone

Single Doorbell Button Wiring

  • For single button activation, a common transformer is the NuTone C905 (see end of article). Rating = 16VAC, 10VA (watts).
  • Neither door buttons nor transformer are polarity specific, unless otherwise noted in manufacturer’s instructions. Either terminal can be mounted to the red or white bell wire (typical wire colors).

Find complete specs on the C905 at Nutone

How to wire a doorbell with one button
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Multiple Doorbell Button Wiring

  • Wiring Diagram for Front and Rear doorbell buttons.
  • Use NuTone C907 transformer. Rating = 16VAC, 30VA (watts). Extra watts = extra power = adequate chime  sound, when longer runs of wire on two button applications is typical.
  • Neither door buttons nor transformer are polarity specific, unless otherwise noted in manufacturers instructions. Either terminal can be mounted to the white or red wire (typical wire colors).

Find complete specs on the C907 at Nutone

Front and rear doorbell wiring diagrams

Transformer and Doorbell Relationship

A wired doorbell needs power to operate, but the 120VAC from the electrical box is too powerful and un-needed for the application. A transformer steps the 120VAC voltage down to 16-20-24 volts to be compatible with doorbell components voltage ratings.

A transformer can be mounted several ways:

  • Located inside the bell or chime enclosure.
  • Installed into a single electrical gang box like a switch, e.g. NuTone C915.
  • Wall mounted via the 4 screw holes in the mounting plate.
  • Mounted to a junction box.
NuTone / Broan C905K Doorbell Transformer

A junction box mounted transformer will either have males threads and a nut, allowing the transformer to mount via one of the junction box knockouts, or use a quick install lock-mount. Power will be delivered from the 120v wires inside the box; connecting to the pigtail wires pre-attached to the doorbell transformer.

**Further specific instructions will be included in product packaging.

Tags : doorbellelectrical