The electrical box has the characteristics of small size, easy installation, special technical performance, fixed position, unique configuration function, not limited by the site, widely used, stable and reliable operation, high space utilization rate, small footprint and environmental protection effect. It is the control center that directs the various components in the power supply line to distribute power reasonably. It is the control link that reliably receives the upper-end power supply and correctly feeds out the load power. It is also the key to obtain whether the user is satisfied with the power supply quality. Improving the operational reliability of the power distribution box is the goal of creating high-quality projects.
The purpose of the distribution box: to distribute electric energy reasonably, and to facilitate the opening and closing operation of the circuit. It has a high level of safety protection and can intuitively display the conduction state of the circuit.
Commonly used distribution boxes are made of wood and metal. Because the protection level of metal distribution boxes is higher, metal is still used more.
Classified by structural features and uses:
(1)Fixed panel switchgear , often called switchboard or power distribution panel. It is a kind of open switchgear covered by a panel. The front has a protective effect, and the back and sides can still touch the live parts. The protection level is low, and it can only be used in industrial and mining enterprises with low requirements for power supply continuity and reliability. Centralized power supply for transformer room.
(2) Protective (that is, closed) switchgear refers to a low-voltage switchgear that is closed on all sides except the installation surface. The electrical components such as switch, protection and monitoring control of this cabinet are all installed in a closed shell made of steel or insulating material, which can be installed on the wall or away from the wall. There may be no isolation measures between each circuit in the cabinet, or a grounded metal plate or insulating plate may be used for isolation. Usually the door is mechanically interlocked with the main switch operation. In addition, there is also a protective table-type switchgear (that is, the console), and the control, measurement, signal and other electrical appliances are installed on the panel. The protective switchgear is mainly used as a power distribution device on the process site.
(3) Drawer switch cabinet. This kind of switch cabinet is made of steel plate to make a closed shell, and the electrical components of the incoming and outgoing circuit circuits are installed in drawers that can be drawn out to form a functional unit that can complete a certain type of power supply task. The functional unit and the bus bar or cable are separated by a grounded metal plate or a plastic functional plate to form three areas: the bus bar, the functional unit and the cable. There are also isolation measures between each functional unit. Drawer-type switchgear has high reliability, safety and interchangeability , and is a relatively advanced switchgear. Most of the switchgears refer to drawer-type switchgears. They are suitable for industrial and mining enterprises and high-rise buildings that require high reliability of power supply, as a centralized control power distribution center.
(4) Power and lighting distribution control box . Most of them are closed vertical installations. Due to different use occasions, the enclosure protection level is also different. They are mainly used as power distribution devices in the production sites of industrial and mining enterprises.
Power distribution box is assembled in closed or semiclosed metal safe by electrical wiring requirement by switchgear, measuring instrument, protective device and auxiliary equipment or on screen width, forms low-voltage distribution box. During normal operation, the circuit can be connected or disconnected by means of a manual or automatic switch. Cut off the circuit or alarm with the help of protective electrical appliances in case of failure or abnormal operation. Various parameters in operation can be displayed by means of measuring instruments, and some electrical parameters can also be adjusted to prompt or send out signals for deviations from normal working conditions.