MasterPact MTZ2 — 1250 A Fixed Power Breaker
The Schneider Electric LV846552 is a MasterPact MTZ2 fixed circuit breaker rated 1250 A at 40 °C, with a service breaking capacity (Ics) of 50 kA at 1150 V AC. This places it in the H10 performance class — the interrupting rating governs fault clearing for high-energy distribution panels, not just the continuous load. Category B selectivity confirms the breaker is listed for full discrimination with downstream devices — critical for maintaining supply to non-faulted loads in a tiered distribution scheme. Rear connection top and bottom keeps the bus run clean in a fixed-mount switchboard; the 115 mm connection pitch matches standard MasterPact busbar risers. Mechanical durability is rated at 25,000 cycles with periodic preventive maintenance; electrical durability at 500 cycles at rated voltage. These are not trivial numbers — for a main breaker that may see only a few operations per year, the mechanical endurance is effectively life-of-installation. The 100 W power dissipation at rated current must be factored into enclosure ventilation; in a sealed IP30 panel, that heat adds to the internal rise and may require derating or forced airflow.
Standards & Compliance Documentation
Operating altitude is 0–2000 m without derating, 2000–5000 m with derating. The manufacturer provides a declaration of performance, IEC certificate, and material compliance declarations (RoHS, REACH) as standard documentation.
Integration — Panel Fit & Mounting
Fixed mounting on rails or a base plate. Dimensions: 537 mm wide × 352 mm high × 300 mm deep. The 300 mm depth is the front-to-back projection behind the panel door — verify swing clearance for the arc chamber and rear connection access. Control is push-button only; no electronic control unit is fitted. Closing response time is 70 ms maximum, breaking time 25 ms maximum.