Avoid water at all times when working with electricity. Never touch or try repairing any electrical equipment or circuits with wet hands. It increases the conductivity of the electric current.
Never use equipment with frayed cords, damaged insulation, or broken plugs.
If you are working on any receptacle at your home then always turn off the mains. It is also a good idea to put up a sign on the service panel so that nobody turns the main switch ON by accident.
Always use insulated tools while working.
Always use appropriate insulated rubber gloves and goggles while working on any branch circuit or any other electrical circuit.
