Classification of distribution boxes
Common distribution boxes are available in two types: wooden and metal. Since metal distribution boxes have a higher protection level, metal ones are more widely used.
Classification by structural characteristics and application:
(1) Fixed panel switchgear, often referred to as switchboard or distribution panel. It is an open-type switchgear with a panel shield. The front side provides protection, but the back and side sides still allow access to live parts, resulting in a low protection level. It can only be used in industrial and mining enterprises with low requirements for power supply continuity and reliability, serving as centralized power supply in transformer substations.
(2) Protective (i.e., enclosed) low-voltage switchgear. It refers to a type of low-voltage switchgear where all sides except the installation surface are enclosed. Electrical components such as switches, protection devices, and monitoring and control devices in this type of cabinet are all installed inside a closed enclosure made of steel or insulating materials, and it can be installed against the wall or away from the wall. Isolation measures may or may not be added between each circuit in the cabinet; alternatively, grounded metal plates or insulating plates can be used for isolation. Usually, there is a mechanical interlock between the door and the main switch operation. In addition, there is also a protective bench-type switchgear (i.e., control console), on the panel of which electrical devices for control, measurement, and signaling are installed. Protective switchgear is mainly used as power distribution equipment at the process site.
(3) Drawer-type switchgear. This type of switchgear adopts a closed enclosure made of steel plates. Electrical components for incoming and outgoing circuits are all installed in removable drawers, forming functional units that can complete a specific type of power supply task. The functional units are separated from the busbars or cables by functional plates made of grounded metal or plastic, forming three areas: busbar area, functional unit area, and cable area. Isolation measures are also provided between each functional unit. Drawer-type switchgear has high reliability, safety, and interchangeability, making it a relatively advanced type of switchgear. In most cases, "switchgear" refers to drawer-type switchgear. They are suitable for industrial and mining enterprises and high-rise buildings that require high power supply reliability, serving as centralized control power distribution centers.
(4) Power and lighting distribution control boxes. Most of them are enclosed and installed vertically. Due to different application scenarios, the enclosure protection levels also vary. They are mainly used as power distribution equipment at the production sites of industrial and mining enterprises.
Structure
The structure of distribution boxes can be divided into two types:
1. Welded structure [3]: Simply cut, bend, and drill holes in sheet metal parts, then weld them together.
2. Assembled structure: Process sheet metal parts separately. After each component is processed, assemble them together, and secure and lock them with screws and tees. This structure has an attractive appearance, simple operation, and can save a large amount of transportation costs.
Distribution boxes, along with power distribution cabinets, distribution panels, distribution screens, electrical cabinets, etc., are complete sets of devices for centrally installing switches, instruments, and other equipment.