What is the difference between mains and sub mains?

Mains electricity is the term used to refer to the electrical supply coming from a power station to the household you live in. The current flows in one direction, then the opposite, continuously. It enters the house via the live wire, which carries the incoming electricity. However, a sub-mains circuit is defined as a circuit that is directly from the main low voltage switchboard, to the sub-main distribution panel.