Like switchgear, circuit breakers, load switches are in this category; control equipment, contactors, relays; protection equipment including fuses, over-voltage protector; and measurement equipment, such as voltmeter, ammeter. Complete set of high and low voltage electrical equipment As an important type of electrical device, complete sets of electrical equipment belong to the category of electrical equipment, similar to switches, contactors, circuit breakers, and transformers, but they have distinct integrated. Electrical switchgear is a complete set of equipment composed of circuit breakers and isolation switches. It is the core component of the power system, so it is responsible for the control, protection and isolation of circuits and equipment, and is also used to regulate power flow, quickly cut off. This handbook is provided for the use of all Departments of the ITER Organization and is addressed primarily to system specifiers, designers and users of electrical components in otherwise non-electrical plant systems, rather than to designers of the power supply systems. They are known as complete switchgear assemblies because they integrate inside them such. From the function and use of the scene, high and low voltage complete sets of equipment is divided into many kinds of it.