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Distribution box technical parameter description and precautions

Parameter Description

  1. The maximum rated current of the main busbar: the rated value of the maximum current that the main busbar can carry.
  2. Rated short-time withstand current: given by the manufacturer, the root mean square value of the short-time withstand current that a certain circuit in the complete set of equipment can safely carry under the test conditions specified in 8.2.3 of the national standard GB7251.1-2005 .
  3. Peak short-time withstand current: Under specified test conditions, the manufacturer specifies the peak current that the circuit can withstand satisfactorily. 4. Enclosure protection level: According to the IEC60529-1989 standard, the complete set of equipment provides the level of protection against touching live parts, as well as the intrusion of foreign solids and the ingress of liquids. Please refer to the IEC60529 standard for specific classification.
  4. Internal partition method: According to the IEC60529-1989 standard, in order to protect personal safety, the switchgear is divided into several compartments in different ways.

The technical parameters of different types of distribution cabinets are very different, and the technical parameters of imported distribution cabinets are basically better than domestic distribution cabinets, but it cannot be considered that imported distribution cabinets are necessarily better than domestic distribution cabinets .




(1) The power distribution system for construction should be equipped with a main distribution box, a distribution box, and a switch box, which should be set up according to the order of “general-divided-open” and form a “three-level power distribution” model.

(2) The installation positions of the distribution boxes and switch boxes of the power distribution system for construction should be reasonable. The main distribution box should be as close as possible to the transformer or external power supply to facilitate the introduction of power supply. The distribution box should be installed as far as possible in the center of the relatively concentrated electrical equipment or loads to ensure that the three-phase loads remain balanced. The installation position of the switch box should be as close as possible to the electrical equipment it controls according to the site conditions and working conditions.

(3). To ensure the three-phase load balance of the temporary power distribution system, two power circuits should be formed for the power consumption and lighting power consumption on the construction site, and the power distribution box and the lighting distribution box should be installed separately.

(4) All electrical equipment on the construction site must have their own dedicated switch boxes.

(5) The cabinets and internal settings of the distribution boxes at all levels must comply with safety regulations, the switchgear should be marked with the purpose, and the cabinets should be numbered uniformly. The power distribution box that is out of use should be cut off and the door locked. The fixed distribution box shall be provided with a fence, and measures shall be taken to prevent rain and smashing.

(6). The difference between distribution box and distribution cabinet. According to GB/T20641-2006 “General requirements for low-voltage switchgear and control equipment empty shells”

Distribution boxes are generally used in households, while power distribution cabinets are mostly used in centralized power supply, such as industrial electricity and building electricity, etc. Both distribution boxes and distribution cabinets are complete sets of equipment, and distribution boxes are low-voltage complete sets of equipment , The distribution cabinet has high voltage and low voltage.