Requirements and standards for electrical control cabinets

An electrical control cabinet is a control cabinet (box) that assembles switchgear, measuring instruments, protective devices and auxiliary equipment in a closed or semi-closed metal cabinet or panel according to the electrical wiring requirements. Its layout should meet the requirements of normal operation of the power system, be convenient for maintenance, and not endanger the safety of personnel and surrounding equipment. This includes (distribution cabinets), (distribution boxes), (electrical control cabinets), etc. During normal operation, circuits can be connected or disconnected by means of manual or automatic switches. When there is a fault or abnormal operation, the circuit is cut off or an alarm is triggered by means of protective electrical appliances. The measuring instrument can display various parameters during operation, adjust certain electrical parameters, and give prompts or signals when deviating from the normal working state. It is commonly used in various power generation, distribution and transformation substations.



The cross-sectional area of the secondary circuit and voltage line wiring in a general low-voltage electrical control cabinet is 1.5 square meters, and the cross-sectional area of the current loop is 2.5 square meters. The current loop refers to the current signal lines of current transformers, ammeters, power factor meters, mutual inductance watt-hour meters, etc. The current flowing through it is 5 amperes. In addition, the power line is yellow, green and red, while the neutral line is blue or light blue (some are gray). Because international standards are also classified as either European standards or American standards. The main circuit should have at least 1.5 square millimeters of black wire, the control line should have 1.0 square millimeters of red wire for AC voltage, and 1.0 square millimeters of blue wire for DC voltage. There is no requirement for the color of the signal line.

Some electrical control cabinets have standards. It's called a standard cabinet, GGD. The standard electrical control cabinet complies with the following standards: "Code for Design of Low-voltage Electrical Apparatus GB50054-1995", "Code for Design of General Electrical Equipment GB50055-1993", "Code for Design of Construction of Industrial Automation Instrument Engineering GB50303-2002", "Code for Control Equipment of Low-Voltage Switchgear Assemblies GB7251-97", "Code for Safety of Electrical Installations GB50171-97 "Code for Installation of Engineering Panels, Cabinets and Secondary Circuit Wiring Construction and Acceptance", but most of the electrical control cabinets are not standard. The reason for not being standard is that when you do the project, you make the size of the cabinet according to the actual situation. Standard cabinets sometimes have too much space and are not practical.