I am doing some wall repair in my home, there is an outlet I want to turn off for safety, how can I find what circuit breaker it's on?
The best way would be with a multi meter or any other electronic device that will help you read electrical signals. 

However, if this does not work (it could mean the wiring between the power supply and the house is faulty), you should check the label of the nearest electricity switch, usually located behind one or more doors along your hallway/bathroom area