A metal-cased appliance has a working earth wire and a fuse in the live wire. A low-resistance fault connects live to the case. The fuse melts and disconnects the live supply.
Which pair describes the main fault-current path before the fuse melts and the case potential after it melts?
Through neutral only; approximately 230 V230\ \mathrm{V}230 V relative to earth.
Through the earth wire; approximately 0 V0\ \mathrm{V}0 V relative to earth.
Through neutral only; approximately 0 V0\ \mathrm{V}0 V relative to earth.
Through the earth wire; approximately 230 V230\ \mathrm{V}230 V relative to earth.
81 exam-style questions on Edexcel GCSE Physics 10.4 Mains electricity, covering 10.4.1 Direct and alternating current, 10.4.2 Live, neutral and earth wires; safety, 10.4.3 Mains wire potential differences and dangers, and 10.4.4 Power ratings and energy use. Each one has a worked solution and a mark scheme showing where the marks go.