HD4 breakers are used in electrical distribution for control and protection of cables, overhead lines, transformer and distribution substations, motors, transformers, generators and capacitor banks. Thanks to the SF6 autopuffer breaking technique, the HD4 circuit-breakers do not generate operating overvoltages, and are therefore also highly suitable for retrofitting, upgrading and enlarging older installations where the motor, cable, etc. insulating materials may be particularly sensitive to dielectric stresses.
- Sealed-for-life poles
- Withstand insulation voltage even at zero relative pressure
- Operation under different climatic conditions
- Stored energy operating mechanism with anti-pumping device supplied as standard
- Fixed and withdrawable versions with front operating mechanism
- Circuit-breaker racking-in and racking-out with the door closed