Why is ring network cabinet called secondary distribution cabinet?

Ring network cabinet with switch can realize network distribution automation, large volume, suitable for ring network power supply, usually used indoors, but also used outdoors, widely used in places with high power supply reliability. It is most commonly used on double-circuit power supply lines.

According to the requirements of power supply system:

Distribution board (box) is divided into power distribution board (box), lighting distribution board (box), metering box, is the last stage of the distribution system equipment.

(1) First-level power distribution equipment, collectively known as power distribution center. They are centrally installed in the company's substations and distribute power to sub-distribution units in different locations. This level of equipment is close to the step-down transformer, so the electrical parameters are higher requirements, output circuit capacity is also larger. 

(2) Secondary distribution equipment, power distribution cabinet and motor control center collectively. Power distribution cabinet used in the load more scattered, less loop occasions; Motor control center for load concentration, more loop occasions. They distribute electrical energy from a circuit in the upper distribution equipment to nearby loads. This level of equipment shall provide protection, monitoring and control of the load.

(3) The final distribution equipment is called lighting power distribution box. They are scattered and small - capacity distribution devices far from the power supply center.

Classification by structural characteristics and uses:

(1) Fixed panel switch cabinet, often called switch board or distribution panel. It is a kind of open switch cabinet with panel shielding, the front has protective effect, the back and side can still touch the live part, the protection grade is low, can only be used for the continuity of power supply and reliability requirements of industrial and mining enterprises, for centralized power supply substation.

(2) protective (that is, closed) switch cabinet, refers to a low-voltage switch cabinet that is closed on all sides except the installation surface. Electrical components such as switches, protection and monitoring controls are installed in a closed enclosure made of steel or insulation material, which can be mounted on or off the wall. Each circuit in the cabinet can be separated without isolation measures, or grounded metal plates or insulation plates can be used for isolation. Usually the door is mechanically interlocked with the main switch operation. There are also protective platform switch cabinet (namely console), control, measurement, signal and other electrical appliances are installed on the panel. Protective switch cabinet is mainly used as power distribution device in process site.

(3) drawer type switch cabinet. This kind of switch cabinet is made of steel plate closed shell, the electrical components of the inlet and outlet circuit are installed in the drawer that can be drawn out, forming a functional unit that can complete a certain kind of power supply task. The functional unit and the bus or cable are separated by functional plates made of grounded metal or plastic, forming three areas of bus, functional unit and cable. There are also isolation measures between each functional unit. Drawer type switch cabinet has higher reliability, safety and interchangeability, is more advanced switch cabinet, the current production of switch cabinet, most of it is drawer type switch cabinet. They are suitable for industrial and mining enterprises and high-rise buildings that require high reliability of power supply, as centralized control distribution centers.

(4) Power and lighting distribution control box. Mostly closed vertical installation. Due to the use of different occasions, the shell protection level is also different. They are mainly used as distribution devices in the production site of industrial and mining enterprises.