Earthing and double insulation reduce shock risk; a fuse or circuit breaker disconnects the supply when excessive current flows. Know where the fuse goes and why breakers can be reset.
Syllabus
First assessment 2019
Course
Physics 4PH1
Exam points
explain how an earth wire carries fault current and trips a circuit breaker
compare fuses and circuit breakers using reset time, replacement and current cut-off
state where a fuse is placed in a mains appliance circuit, including the live wire