What an RMU does
A ring main unit combines switching and protection functions for medium-voltage distribution. Appropriate network arrangements allow a faulty section to be isolated while alternative supply paths support service continuity.
Typical functional units
Configurations may combine incoming and outgoing feeders, transformer protection, metering, busbars and monitoring. Switching and protection can use load-break switches, fuses or circuit breakers, depending on the specified duty.
Insulation and installation
Air-, gas- and solid-insulated designs offer different footprint and maintenance characteristics. RMUs are used in urban distribution, industrial facilities, transport infrastructure and renewable energy connections.