What electrical safety procedure is described below if you are going to work on something electrical you should first disconnect it completely from its electrical source then you have to make sure?

Lock Out, Tag Out

This is the process of disconnecting the power supply, locking it so no one can turn it back on and tagging the lock so people know why it is locked out and who locked it. It is against the law in some states and OSHA for someone else to unlock it.