How to Wire the Transformer When Installing a Doorbell

If you are replacing a doorbell, it's a good idea to also replace its transformer. This assures that you have adequate voltage going to your new bell. These transformers are usually found in either the attic or basement and connect directly into your home's electrical junction box or other power source.

Difficulty: Moderate

Instructions

1. Turn off the electrical power to your home. These transformers are low-voltage units, but you are connecting them to your main power source.

2. Find the old transformer, and disconnect the black and white wires from the junction box (on 1 side of the transformer) and the 2 wires connected to the opposite, or low voltage side of the transformer.

3. Connect the new transformer to the junction box by attaching the black, or power, wire to the black lead in the junction box and the neutral, white wire to the white lead. There may also be a green wire attached to the transformer, which is a ground wire. This isn't used in older houses and can be capped off.

4. Attach the 2 wires coming from your doorbell to the low voltage side of the transformer by connecting them to the 2 screws on the opposite side of the unit. It doesn't matter which wire goes to which screw.

Tips & Warnings

• Some transformers may come with a plug that can be inserted into any electrical outlet. There are also some doorbell units that have transformers built into them or are designed to operate wirelessly.