Vacuum switches have been widely adopted in medium voltage electrical devices due to its excellent breaking capacity and maintenance-free characteristics. To outdoor distribution switches, the importance of superior performance, maintenance-free design for outdoor operation, safety and reliability is even more significant. To adapt to the development of distribution automation in China, and to meet the need of distribution lines for automated and highly reliable primary equipment, we have introduced the technique and design from Toshiba in Japan and developed the VSP5 Pole-mounted Vacuum Switch. There have been more than 200,000 VSP5 in operation globally, and more than 20 provinces, cities and autonomous regions in China have adopted this model. Due to its superior performance and maintenance-free design, this switch has been widely applied in overhead distribution lines.