Of the three connecting wires in a household circuit: Which two of the three wires are at the same potential? In which of the three wires should the switch be connected?

Of the three connecting wires in a household circuit: Which two of the

1.	Of the three connecting wires in a household circuit: Which two of the three wires are at the same potential? In which of the three wires should the switch be connected?
Answer» Neutral wire and Earth wire are at same potential and the switch be connected to live wire.