1)Disconnect completely meaning that the electrical installation must be disconnected from life parts on all poles..
2) Secure against reconnection
3) verify that the installation is dead
4) Carry out earthing and short circuiting
5) provide protection against adjacent live parts
6) avoid water at all times when working with electricity
7) never use equipment with frayed cords, damage insulation or broken plugs.
I hope this helps :)