Stationary circuit breaker with Sentinel trip unit 42kA 400A 3P HW1N304FB

Fixed Circuit Breaker with Sentinel Trip Unit – 42 kA, 400 A, 3P

This device is a fixed, non-withdrawable version of an air circuit breaker with an integrated sentinel trip unit, designed for installation in low-voltage switchboards. It has been engineered for operation in installations with high safety and reliability requirements – where precise protection of circuits against short circuits and overloads is essential.

The built-in sentinel trip unit functions as an integrated module – it does not require additional modules or external controllers. It operates based on current and time parameters that are factory-set and not configurable by the user. This simplifies installation and eliminates the risk of errors during parameter setting.

The main terminals are designed for busbar connections – direct cable connection to the terminals is not possible. This means the device must be installed within a busbar system (e.g., switchboard busbars), which is typical for large industrial or commercial installations. DIN rail mounting is not possible – the device is permanently secured using screws or a supporting structure.

The rated short-circuit breaking capacity at 400 V is 42 kA – meaning the circuit breaker can safely interrupt a short-circuit current of this magnitude without damaging the internal components. This is a critical parameter for circuits supplying machines, transformers, or large switchboard installations.

It features 3 poles and operates within a voltage range of 440 to 690 V, making it suitable for both 400 V three-phase systems and higher-voltage industrial systems (e.g., 500–690 V). The protection degree IP2X ensures protection against contact with fingers or tools with a diameter greater than 12 mm – sufficient for enclosed switchboard interiors.

The unit includes an off indicator – a physical element (e.g., a red flag or sliding indicator) that visibly indicates the device status: whether it is in the "ON", "OFF", or "TRIPPED" position. This facilitates diagnostics and ensures safety during operation.

Additionally, the device has four changeover auxiliary contacts – allowing status signaling (ON/OFF) to automation or central control systems. There are no normally open or normally closed contacts – therefore, it cannot be used as a signaling relay without an additional module.

A motor operator is not part of the standard configuration, but the device supports its addition as an option – simply install the appropriate module during assembly.

Earth fault protection is not available in this version – if protection against ground insulation faults is required, a separate RCD module or a G-type trip unit must be added.

The sentinel trip unit is an integral part of the device and does not include additional functions such as time-delay overload protection or selectivity. It provides pure short-circuit protection.