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Ring Main Unit (RMU)

Ring Main Unit (RMU)

  Ring Main Unit,   RMU   is a compact, enclosed and sealed type of Switchgear used for medium voltage power distribution. It is a complete Switchgear in itself. A complete Switchgear means, assembly of required switching devices, protection device as well as metering device. RMU of different voltage (mostly 12 kV and 24 kV) and current ratings are available.  Indoor as well as outdoor types of Ring Main Units are available. Ring Main Unit comprises of one incomer feeder and one or more outgoing feeder. The incomer feeder is either Vacuum Circuit Breaker or SF 6  Circuit Breaker with associated Disconnect Switch and Earth Switch. This incomer feeder is given with the provision of bushing protruding from the enclosure of RMU for supply cable connection. A typical Ring Main Unit is shown in figure below. Outgoing feeder comprises of Load Break Switches with associated Disconnect Switch and Earth Switch. Provision for cable connection is provided in outgoing feeder. The  Load Break Switch