Step-by-step explanation:
It is the safest way to shut down a circuit by switching off the main switch. If you haven't switched off the main switch and started directly working on it you are open to all kinds of harm one being electrocuted (since high current flows through the electric circuits due to the short circuit or overloading, the fuse wire heats and melts down) other methods of avoiding being electrocuted after turning the main switch off is by using insulating tools such as tools made of wood.