Stationary circuit breaker with sentinel trip unit 42kA 1250A 3P HW1N312FB

Stationary air circuit breaker with Sentinel trigger

This device is a stationary air circuit breaker with a rated current of 1250 A, designed for installation in medium‑ and high‑power switchgear where reliable short‑circuit and overload protection is required. Its making‑capacity at 400 V is 42 kA — meaning it can safely interrupt a circuit even under extreme fault currents typical of large industrial or infrastructure installations.

It has three poles and a busbar connection — facilitating integration with switchgear busbars without the need for conventional wiring. It is not mounted on a DIN rail, nor does it have an integrated motor drive, but it supports an optional drive — allowing remote control or system automation without replacing the device.

The built‑in trip indicator provides immediate visual information on the device status — no need to open the enclosure to check whether the breaker is in the “off” position. Four auxiliary switching contacts enable connection of status signalling (e.g., to a control panel or SCADA system), which is essential in automated installations.

IP2X protection class offers basic protection against accidental contact with live parts — sufficient for closed switchgear, but it does not protect against dust or water. The rated operating voltage range is 440–690 V AC — ideal for industrial networks of 500–600 V.

The closing response time is 45 ms — providing fast and precise operation on automatic closing. The internal resistance is only 25 µΩ — minimizing heat loss and reducing the risk of overheating under prolonged load.

There is no built‑in earth‑fault protection or under‑voltage release — so if these functions are needed, they must be added externally. It also lacks an integrated protection unit — this is a basic element that requires a separate trigger (e.g., Sentinel) for full functionality.

Compliant with PN-EN 60947-2 and carries EU and UKCA declarations of conformity — guaranteeing its approval for use in the European Union and the United Kingdom. Mechanical endurance of 30 000 cycles and electrical endurance of 8 000 cycles ensure the device is designed for long‑term operation under intensive conditions.