My doorbell button remained stuck depressed until the transformer failed. My house is 6 years old and the electrician mounted the 24v doorbell transformer directley to the exterior of the circuit breaker panel. The old transformer has 2 wires - one black and one white. The white is connected to the ground bar and the black to the breaker switch. Now the only transformers I could find had three wires - 2 black and one green.

How do I connect a 3 wire transformer to my circuit breaker? Do both black wires go to the breaker switch and the green to the ground bar?

 

A doorbell tramsformer is usually 17v. Are you sure he used a doorbell transformer?

If you are sure it is a 120v doorbell transformer hook one black to the breaker and one black to the neutral. Hook the green to ground bar if present or the neutral if no ground bar.

Terminology tip: It is usually just called a "breaker" not a breaker switch. Save your fingers some typing.

 

Ray, thanks for responding. The old transformer indeed says 24v.

I followed your advice and connected one black to the breaker and other black and green to the neutral bar. It works!!

Thanks for you Help!