Before working on any electrical circuit – advice from a professional electrician
“Before working on any electrical circuit isolate the supply by switching off the main switch and remove the fuse to the circuit that you are working on, If it is a circuit breaker switch off the main fuse and circuit breaker and remove the wires from the top of the circuit breaker. Place a sign saying that you are working on the circuits on the consumer unit, then nobody will restore the power whilst you are working on it.” – Will Irving