HK load switch (hereinafter referred to as the switch) is suitable for the circuits (AC 50Hz, single-phase rated voltage of 220V, 380V and below for three phase, rated current up to 100A), and serve as master switch, branch circuit switch and operating switch of lights, heater to protect against as a short circuit of loaded electrical units and small capacity circuits which are manually switched on and off in an infrequent manner.