Draw-out circuit breaker with sentinel trip unit 42kA 1250A 3P HW1N312DB

Withdrawable air circuit breaker with Sentinel trip unit, 1250 A, 3‑pole, 42 kA

This device is a withdrawable air circuit breaker designed for industrial and commercial installations where reliable short‑circuit and overload protection at high currents is required. Its construction allows safe and rapid replacement without disconnecting conductors – simply pull out the module to access the interior. This solution significantly reduces service time and minimizes the risk of installation errors.

The built‑in Sentinel trip unit enables precise adjustment of the protection characteristic to the load type – ideal for circuits with motors, transformers, or other equipment with high inrush currents. It does not include built‑in earth‑fault protection or an integrated over‑voltage trip – such protection must be provided by external devices or a control system.

Main circuit connections are not fixed – they are linked via a separate housing part. This means installation requires appropriate terminals (e.g., busbars or cables with suitable lugs), but it offers flexibility in wiring layouts. The trip indicator on the housing shows the device status – closed or tripped – without opening the enclosure.

IP2X protection class provides basic protection against accidental contact with live parts, but does not protect against dust or water – the device is intended solely for installation in closed switchgear cabinets. Rated voltage 440–690 V AC makes it suitable for medium‑voltage industrial systems, e.g., 400/690 V switchgear.

Short‑circuit rating 42 kA at 400 V means it can safely interrupt very high fault currents – crucial in modern low‑impedance networks. Closing response time is 45 ms, fast enough to prevent damage from brief over‑voltages.

4 auxiliary switching contacts are built in, allowing status signalling (e.g., “closed”, “tripped”) to SCADA systems or control panels. There are no breaking contacts, so it cannot be used as an isolation device without additional equipment.

External AC supply is required for the trip unit and auxiliary contacts. A motor drive is not built in but is optional, enabling remote control or automation of the tripping process.

The breaker complies with PN-EN 60947-2:2018+A1:2020 and meets RoHS and REACH requirements. Confirmed mechanical life is 25 000 cycles and electrical life 6 000 cycles at full load. Total power loss at 1250 A is approximately 187.4 W, influencing cabinet ventilation selection.

It is not mounted on DIN or TH rails – it requires a fixed installation in a switchgear cabinet using special brackets or a mounting frame.