Phase short circuit capacity is less than the rated breaking capacity of the fuse cap

Phase short circuit protection system to ensure the capacity is less than the rated breaking capacity of the fuse cap, but must be Circuit breaker the lower limit of the rated breaking capacity. If the fuse rated breaking capacity (generally refers to the upper limit) is too large, the system is likely to be protected three-phase short air circuit breaker capacity Rated capacity is less than the lower limit of the fuse, resulting in the melt blown difficult interrupter, and ultimately lead melting tube burned, explosions and electric meter. Some power supply unit is still in the rural power grids peak, in the selection of such fuses must be strict product quality, protect the network of qualified equipment, taking note of its rated breaking capacity of the upper and lower limits.