HKKW2 Series of intelligent frame circuit breakers HKKW2 Series of intelligent universal circuit breaker is mainly used in AC. 50Hz, rated voltage of 400V(380V)íó690V(660V) and rated current between 630A-6300A power distributing work-net to distribute Elec. power and protect equipments from being damaged by over-load, short-circuit, under voltage and grounding fault, having many protective functions and ability of realizing accuracy protective action in selectivity, improving reliability and quality of supplying Elec. power. The breaker is widely used in modern Elec. power distributing network.