RDQ1 series Dual Power Supply Auto-Transfer Switch is suitable for the power- supply system of AC 50Hz, rated operating voltage 400V, rated operating current 63 A and below. It can selectable switch between two circuit power supply according to requirements. This product has the protective functions of over-load, short-circuit, under-voltage, meanwhile, it also has the functions of fire protection, double breaking and output the closing signal, which is especially suitable for the lighting circuit of the office building, shopping mall, bank, high-rise building that required toe fire protection.