Usage, Principle, And Classification of Low Voltage Distribution Box

Low-voltage distribution box is a device responsible for controlling, protecting, converting, and distributing electrical energy at the terminal end of the low-voltage power supply system. It is mainly composed of wires, electrical components including isolation switches, circuit breakers, and the box itself, and serves as a circuit distribution box for all users.

Working principle of low-voltage distribution box

Low-voltage distribution box is a low-voltage distribution device consisting of switchgear, measuring instruments, protection devices, and auxiliary equipment assembled in a closed or semi-closed metal cabinet or screen. It can manually or automatically turn on or off the circuit during normal operation. During faults or abnormal operation, protection devices can cut off the circuit or trigger an alarm. By measuring instruments, various parameters during operation can be displayed, and some electrical parameters can be adjusted to prompt or signal deviations from normal working conditions. It is commonly used in power generation, distribution, and substations.

Uses of low-voltage distribution box

It is convenient for management and it is conducive to maintenance when circuit faults occur. Distribution boxes and cabinets, distribution panels, and distribution screens are sets of devices for installing switches, meters, and other equipment. Commonly used distribution boxes are made of wood and iron plates, and due to the large demand for electricity, iron is more commonly used. The purpose of the distribution box is undoubtedly to facilitate power supply and to measure and determine the stoppage or supply of electricity.

Classification of low-voltage distribution box according to structural characteristics and applications

Fixed panel-type switch cabinet, commonly known as a switchboard or distribution panel

It is an open-style switch cabinet with a panel cover on the front side for protection, but the back and side sides can still touch the live part, and the protection level is low, and it can only be used for industrial and mining enterprises with low requirements for power continuity and reliability, serving as a centralized power supply in transformer rooms.

Protective (i.e., enclosed) switchgear

Refers to a low-voltage switchgear in which all sides except the installation surface are closed. The electrical components such as switches, protection, and monitoring control are installed in a closed enclosure made of steel or insulating materials, which can be installed against or away from the wall. No isolation measures are required between each circuit, and a grounding metal plate or insulating plate can be used for isolation. Usually, the door is mechanically interlocked with the main switch operation. In addition, there is a protective type table type switch cabinet (i.e., control cabinet), which is equipped with control, measurement, and signal electrical devices on the panel. Protective switchgear is mainly used as a distribution device for production sites.

Drawer-type switchgear

This type of switchgear is made of steel plates, and the electrical components of the incoming and outgoing line circuits are installed in drawers that can be pulled out, forming functional units that can complete a certain type of power supply task. A grounding metal plate or plastic functional board is used to separate the functional units from the busbars or cables to form three areas: busbars, functional units, and cables. There are also isolation measures between each functional unit. Drawer-type switchgear has high reliability, safety, and interchangeability, and is a more advanced switchgear. Currently produced switchgear is mostly drawer-type switchgear. They are suitable for high requirements for power supply reliability in industrial and mining enterprises and high-rise buildings, serving as a centralized control distribution center.

Low-voltage distribution boxes for power, lighting, and motors

They are mostly enclosed and vertically installed, with different levels of protection depending on the application. They are mainly used as distribution devices for production sites of industrial and mining enterprises.

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