1. Medium-voltage switchgear is primarily designed for end-user applications. It offers comprehensive functionality and generally has a larger footprint. Ring Main Units (RMUs), on the other hand, are mainly used in ring network systems to connect two power sources or different sections of a distribution network. Their primary function is sectionalizing the network, resulting in a more compact design and a single-purpose application. Due to these different purposes, their structures and component selections vary significantly. Medium-voltage switchgear can be categorized into incoming/outgoing feeder panels, metering panels, transformer panels, station service transformer panels, and more, whereas RMUs mainly serve as interconnection switchgear. Medium-voltage switchgear is typically equipped with automatic protection devices that send signals and trip the circuit breaker in the event of a fault, disconnecting the power supply. Most commonly, VS1 vacuum circuit breakers are used. RMUs generally do not include such protection devices; instead, internal fuses melt under fault conditions to interrupt the circuit. Common switching devices include indoor AC high-voltage load break switch-fuse combinations or SF6 load switches.

2. As mentioned above, the RMU serves a single purpose—connecting different sections of a power network. It is generally not used for the control, protection, or metering of specific electrical equipment. If these functions are required, medium-voltage switchgear should be selected instead.

3. In systems involving high voltage, high-voltage metering should always be considered first. Low-voltage metering should only be adopted when high-voltage metering is impractical. In such cases, the low-voltage metering cabinet should be installed ahead of the low-voltage incoming cabinet and behind the transformer. Although the metering cabinet may appear not to be protected by the incoming cabinet, it is generally protected by the transformer's high-voltage switching device.