The LV846212 is a MasterPact MTZ2 4-pole drawout circuit breaker rated 1250 A at 40 °C. For selectivity coordination, Category B means it has intentional short-time delay, so downstream breakers trip first; the 100 kA Icw for 1 second gives the time margin to achieve full discrimination in a distribution panel.
Deployment context
Drawout mounting means the breaker chassis stays wired in the switchgear while the moving portion racks out for maintenance or replacement — standard for main and tie breakers in 400 V to 690 V industrial distribution where uptime matters. The 403 mm depth and 556 mm width fit standard low-voltage switchgear cubicles; connection pitch is 115 mm. Front and rear connection options allow either cable or busbar entry without reconfiguring the cradle.
Rated for isolation — the open contacts provide a visible gap that meets the safety disconnection requirement. IP30 enclosure protection keeps tools and fingers out but is not washdown-rated; the breaker lives inside a switchgear cubicle, not on the open floor.
Electrical durability and thermal budget
Electrical durability: 10,000 cycles at 440 V AC, 50/60 Hz at In per EN/IEC 60947-2 AC-23A, and 6,000 cycles per AC-3. Mechanical durability is 15,000 cycles with periodic preventive maintenance. Maximum breaking time is 25 ms; closing response is 70 ms. Power dissipation at rated current is 230 W — factor that into the cubicle ventilation calculation.