The provided wiring diagrams are based on the NuTone 2-note door chime, but the common wiring configurations should pertain to all other brands of chimes as well.
*Please consult your specific brand of chime for reference.
NuTone Door Chime and Transformer 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?
Single Button Doorbell Wiring Instructions
- 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).
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Double Button Doorbell Wiring Instructions
- Diagram for FRONT and REAR door 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).
What’s a Transformer and its Purpose for Doorbell Installation?
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.
Junction Box Transformer Mounting (as shown):
The 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.