The RW12 series outdoor high-voltage AC fuse, commonly known as "drop-out fuse", is a type of short-circuit protection switch commonly used in branch lines of power distribution lines and distribution transformers. It has the characteristics of being economical, easy to operate, and highly adaptable to outdoor environments. It is widely used in 10-35kV power distribution lines and the primary side of distribution transformers as protection and for equipment switching operations. It can reduce the scope of power outages because it has a distinct break point; it has the function of a disconnect switch, creating a safe working environment for maintenance sections of lines and equipment, and increasing the safety sense of maintenance personnel. Installed on the upper end of the high-voltage side of the distribution transformer, it can serve as the main protection for the distribution transformer.