Ensuring a reliable supply of electricity to commerce, public institutions, and industrial equipment has become even more essential in recent years due to circumstances such as the increasing sophistication of the information society and the construction of high-efficiency production equipment. Switchgear are key components in electricity distribution systems, and in addition to the requirement for high reliability they are also subject to a diverse range of other requirements associated with advances in technology including safety, ease of inspection and maintenance, and consideration for the environment. Hitachi has developed switchgear with solid-insulated bus bars to meet diverse needs by utilizing various technologies including a vacuum disconnecting switch, improved safety through the use of solid-insulated bus bars, and maintenance savings made possible by integrating the main circuit elements into a single unit.