The LV846166 is a Schneider Electric MasterPact MTZ2 fixed-mount circuit breaker, 3-pole, rated 3200 A at 40 °C. It's built for main incoming or large feeder protection in industrial power distribution — the kind of duty where you need the full 100 kA breaking capacity at 440 V AC (H2V performance tier) to handle high-fault upstream busses without cascading.
Push that ambient higher and you derate — the -25...70 °C operating range tells you the thermal limits, but the nameplate rating holds only at 40 °C. For a 3200 A main in a hot switchroom, that derating curve matters. The Ics equals Icu here — meaning after clearing a fault at full rating, the breaker is still rated to carry and switch again. That's Category B selectivity, so you can coordinate downstream breakers without worrying about nuisance tripping on a fault that should stay local. Short-time withstand (Icw) is 100 kA for 0.5 s and 1 s, dropping to 75 kA for 3 s. That's the thermal and mechanical stress the breaker can take during a delayed trip — critical for selective coordination with downstream devices that need time to clear a fault first. Dimensions: 422 mm wide, 352 mm high, 300 mm deep. Fixed mount on rails or base plate. Connection pitch is 115 mm.
Built for the panel, not the lab
This is a current-production part — lifecycle stage is active. That means you can spec it into a new panel design without worrying about a last-time-buy window closing mid-project. Spares for an existing MTZ2 installation are straightforward to source. Standards compliance covers the essentials for distribution gear: EN/IEC 60947-1 (general rules), EN/IEC 60947-2 (circuit-breakers), and Annex H for EMC. Also IEC 61557-12 for measuring equipment. Power dissipation is 420 W at rated current. That's not trivial — factor it into the enclosure ventilation calculation.
What it shrugs off
IP30 protection means it keeps out tools and wires larger than 2.5 mm, but it's not sealed against dust or moisture. In a clean indoor switchroom that's fine. If this breaker ends up in a dusty environment — say, a cement plant or mine substation — you'll want it in a proper enclosure, not open-mounted. Operating altitude: full rating up to 2000 m, derated from 2000 to 5000 m. For high-altitude installations (mining in the Andes, for example), account for the reduced dielectric strength and cooling at altitude. Mechanical durability is 15,000 cycles with periodic preventive maintenance. Electrical durability at rated current in AC-23A duty (switching motor loads or similar) is 5000 cycles at 440 V. That's not a switch you'd use for daily cycling of a motor — it's a distribution breaker, designed to stay closed and clear faults, not to be the operational disconnect.