[header] How to replace a doorbell [title] Turn off the electricity to the doorbell. [step] Even though there's not much current running through it, the doorbell is an electrical appliance. Find the switch indicating the doorbell unit on your home's circuit breaker and flip it to the " off " position. 
This will stop the flow of electricity and allow you to work safely. [substeps] Attempting to remove or modify your doorbell without first making sure that the electricity is off could result in a nasty shock.