What is the line,neutral,ground?
The “line” wire is also known as “hot” wire. Electricity flows from the hot wire to the neutral wire via the equipment connected to the socket.
The neutral and the ground are connected to the same point in the electrical box somewhere in the house.
Any metal casing on the equipment is usually directly connected to ground. This will protect the person from electric shock if he/she touches the metal casing ,in case the metal casing is accidentally connected to the hot wire.