HD4/R circuit breakers can be used in all medium voltage secondary distribution systems and MV/LV transformer substations, in factories, industrial workshops and the services sector. Thanks to installation (on request) of the self-supplied PR521 microprocessor-based overcurrent release, HD4/R circuit breakers are suitable for use in unmanned MV/LV transformer substations without auxiliary power supply. Product scope Medium voltage gas circuit breakers with lateral mechanical actuator (spring mechanism) for secondary distribution up to 36 kV, 1250 A, 25 kA. Key benefits The compact medium voltage SF6 circuit-breaker solution for low-duty distribution Increased safety and protection thanks to optional SF6 low-pressure signaling device and interlocks Easy and fast installation as a result of the optional integrated solution: onboard-tested relay and current sensors/trasformers Ideal solution for metal-clad switchgear Key features Modular spring-operated mechanical actuator ensuring easy operation even without auxiliary supply Interchangeable with VD4/R Performs fast operating cycle Suitable for single-step and back-to-back capacitor switching Vacuum Circuit Breaker