Cambridge IGCSE Physics · Syllabus 0625 · Electricity and Magnetism
The mains circuit and its protective devices
What is The mains circuit and its protective devices?
A mains circuit consists of a live (line) wire at a high potential relative to earth, a neutral wire near earth potential, and an earth wire connected to any conducting casing; the switch, the fuse and the trip switch are all placed in the live wire so that operating one disconnects the appliance from the dangerous potential.
This definition is part of the Electricity and Magnetism chapter in Cambridge IGCSE Physics.