NS series moulded case circuit breaker is one of the most advanced type breakers in the world, which adopt international adv-anced design and manufacture technology. They are suitable for short circuit and overload protection for circuit of Ac 690V 50/60HZ, rated current from 12.5A to 630A. It is rated insulation voltage is 690V. It can make and break non-frequently the circ-uit in the normal conditions. It takes protect effect when mouse cage motors non-frequent start, breaking off working and protecting overload, short circuit and lacking voltage.