The trip units are designed to protect circuits and/or the equipment connected to these circuits and exist as electromechanical or electronic devices. Numerous electromechanical types are available as thermal magnetic devices with overload and short-circuit protection or magnetic-only types providing short-circuit protection. Electronic devices offering wide setting ranges and a more sophisticated level of protection are available in several versions. Each trip unit has a setting area finished with a sealable transparant trip unit door.


Electromechanical devices

Devices available in a current range of 16 to 1250A(1) as single, two, three or four pole devices. The electromechanical trip units exist as thermal magnetic, magnetic-only and generator protection models.

The high performance thermal magnetic trip units exist as selective and non-selective versions and are equipped with a fault indicator that distinguishes between overload and shortcircuit events in accordance with HD 384.

This patented safety feature allows users to reduce downtime by resetting the breaker directly after an overload event.


Electronic devices SMR1 and SMR2

The SMR1 and SMR2 types offer adjustable overload and selective short-circuit protection. The SMR1 range is designed for simplicity and includes numerous exciting features as an overload signalling option, a built-in temperature sensor and rating plugs suitable for both line and motor protection.

The SMR2 has been designed to provide a flexible solution for all protection scenarios.The device is available in two versions, each allowing the user to conveniently tailor his protection to meet individual circuit requirements.

The available options include adjustable overload pickup values, overload trip time characteristics, short time pickup circuit values, short time delay circuit trip times and energy values. The trip unit can be equipped with a ground fault protection and is also available with a load shedding option.