Fuse is an electrical safety device that interrupts current when excessive current flows. First used by Breguet for telegraph stations in 1864. Thomas Edison patented the first fuse in 1890
UK LV networks earthing determined by Low Voltage Supplies. High impedance system allowed for 11kV LV supplies with user-owned transformers. Channel Tunnel example shows emergency lighting can use high impedance
IEC/EN 60335-1 covers household appliances up to 480VAC input voltage. Part 1 addresses general requirements, part 2 covers specific device types. Over 100 device types listed in part 2
Circuit breaker is a switching device that can close current under normal and abnormal conditions. Divided into high-voltage (above 3kV) and low-voltage types. Functions as fuse switch with overheating and underheating relays. Widely used in power distribution systems
EN 61558-2-16:2009/A1:2013 modifies European standard for SMPS safety. Approved by CENELEC on September 16, 2013. Available in English, French, and German versions
Color LCD 3.5-inch dot matrix display shows all test data. Anti-trip technology with 2 or 3 wire for RCD testing. High loop impedance testing up to 2Ω with 0.001Ω resolution. RCD testing for AC, A, F, B, EV and Variable types. Earth resistance testing with 2 or 3 wires