Side terminal faults often destroy or affect the normal operation of power consumption. For example, if the side terminal wiring of differential maintenance in a substation is wrong, the transformer will trip by mistake when the load on the transformer is large or when there is a through phase short circuit; if the line maintenance wiring is wrong, once the system breaks down, the circuit breaker will not trip for the trip, and if the line maintenance wiring is wrong, the device will be damaged and the power system will collapse If there is a problem in the measuring circuit, it will affect the measurement, charge less or more users' electricity, and it is difficult to determine whether the power quality is qualified. Therefore, although the side terminal is not the main body, it plays an extremely important role in ensuring the safety of power consumption and providing qualified power to users.

The completion of control system performance and the reliability of its work, the convenience and quality of operation, commissioning, maintenance, etc. Division of electrical control cabinet components. Due to the different positions of various electrical components and devices, when the side terminals form a sound electrical control system, they must be divided into components. The criteria for dividing components are: (1) combining components with similar functions; (2) reducing the number of wires between components as much as possible, and placing the control appliances with close connection in the same component; (3) separating the strong and weak current controllers to reduce interference; (4) drawing a beautiful picture for the force chart, combining the appliances with similar dimensions and weights; (5) for the electrical control system The system is convenient for inspection and debugging, and combines the components that need frequent conditioning, maintenance and wearing.

In order to facilitate the installation, operation and maintenance, the connection between all the equipment in the side terminal shall stop labeling, which is the side terminal labeling. The label usually uses numbers or the combination of numbers and words, which indicates the nature and use of the circuit. The basic criterion of circuit marking is: if the control cable is to be used to stop contact between the equipment through the terminal block, the marking shall be stopped according to the circuit marking. In addition, the connection between some equipment installed on the top of the screen and the equipment inside the screen also needs to pass through the terminal strip. At this time, the top equipment can be regarded as the equipment outside the screen, and the corresponding label shall be given on the connection line according to the circuit number criterion.