Low price and compact size dual power auto transfer switch (ATS) with high-breaking mini circuit breaker, selectable rated operating current 6A, 10A, 16A, 20A, 25A, 32A, 40A, 63A, works at 400VAC 50Hz/ 60Hz power supply system, 3-pole or 4-pole ATS changeover switch, reliable auto and manual operation, simple structure, easy operation and long service life.