RMSYS switchboard (Ring Main Unit - RMU) is composed by a stainless steel tank containing all the switching device and live parts: three position on-load switches (closed, open and earthed), vacuum circuit breaker or fuses for the protection of the transformer and/or outgoing lines. A relief valve ensures the safety in the event of overpressure inside the container, in accordance with the standards IEC 62271-1. A manometer placed on the front constantly monitors the internal pressure. The switchboard is completed with a supporting metal structure divided into separate operating units.

Main electrical characteristics
Rated voltage kV 12 24
Rated power-frequency withstand voltage 50Hz 1min kV (r.m.s.) 28 (42)* 50 (75*)
Rated lightning impulse withstand voltage kV (peak) 75 (95)* 125 (150)*
Rated frequency Hz 50-60
Rated current main bus bars up to A 630
Rated current functional units A 630
Short-time withstand current kA 20 - 3s
Peak value kA 50
Withstand internal arc kA 20 - 1s
Protection degree stainless steel tank IP 67