To effectively enhance power supply stability, customers can obtain switch-mode power supplies from two directions, typically connecting the power grid in a loop configuration. This type of power supply method is commonly referred to as ring main supply. In 10KV distribution systems for industrial plants, residential complexes, seaports, multi-story buildings, and other communication facilities, due to their small load capacity, the high-voltage power circuits are usually controlled by load power switches or vacuum contactors, and equipped with high-voltage fuses for maintenance. This system software is usually provided by ring main supply, commonly known as a ring main cabinet.

Ring network refers to the circular distribution network, where the power transmission lines form a closed loop. The power supply switches provide power to the circular transmission lines, and then high-voltage circuit breakers distribute power outward to the distribution equipment. The characteristic is that each distribution equipment loop can not only obtain switch power from its left-hand transmission line but also from its right-hand transmission line. When an anomaly occurs in the left-hand transmission line, it will revert to power from the right-hand transmission line, and vice versa when an anomaly occurs in the right-hand transmission line. Thus, although the total switch power is supplied from one side, each distribution equipment loop appears to have dual power supply, thereby enhancing the stability of power supply.

Ring main cabinets refer to the switchgear (group distribution switchgear) at each distribution equipment loop, which is part of the ring main bus. In other words, the ring main bus is formed by connecting the busbars of each distribution cabinet. Each distribution cabinet is known as a ring main cabinet. In fact, it is not possible to see the meaning of a ring main without extracting an individual ring main cabinet.

The rated voltage of this ring main cabinet is not high, so the high-voltage circuit breakers in the ring main cabinet generally do not use complex disconnect switches, but instead opt for simple fuse high-voltage load switches. In other words, the high-voltage circuit breakers in the ring main cabinet are typically load switches. The load switches in the ring main cabinet handle normal electrical currents, while the circuit breakers disconnect short-circuit capacities; the two are combined to replace the disconnect switches. Naturally, this is limited to a certain volume.