The LV839075 is a MasterPact MTZ3 drawout circuit breaker rated 3200 A continuous at 40 °C — that's the full-frame current for a 3-pole ANSI breaker, sized for the main incoming feed or a large bus tie in a 635 V AC switchboard. The breaking capacity code delivers 200 kA Icu at 254 V AC 60 Hz per ANSI C37.50, stepping down to 130 kA at 635 V AC 60 Hz, so it safely interrupts fault currents up to utility-transformer levels without cascading upstream. Integral instantaneous protection is set at 243-297 kA, meaning the magnetic trip operates on a hard short rather than a moderate overload — selectivity with downstream feeders stays intact. The 100 kA Icw for 0.5 s (ANSI C37.50) gives the breaker short-time withstand for delayed-tripping coordination schemes, common in industrial distribution where you want the feeder breaker to clear first. This unit ships without a Micrologic trip unit, so the buyer specifies the protection curve separately — the breaker frame accepts the full Micrologic range (electronic, with or without display, for LSIG or LSI patterns). Mechanical durability is 10,000 cycles, electrical durability 1,000 cycles per ANSI C37.50, which is typical for a drawout air breaker used as a main or tie — not a daily-operating contactor, but built for decades of infrequent switching. The 9 ms maximum breaking time means arc extinction happens within one half-cycle at 60 Hz, limiting let-through energy for downstream equipment.
Drawout mounting on base plate rails — the breaker chassis slides into a fixed cradle, so the line and load connections stay in the switchgear while the breaker is racked out for maintenance or replacement. The connection pitch is 230 mm (9.06 in), matching standard ANSI drawout cubicle cutouts. Overall dimensions: 444.3 mm wide (17.5 in), 426.8 mm deep (16.8 in), 438.8 mm high (17.3 in) — verify the switchgear cell height clears the arc-chamber top, especially in older gear where the bus riser limits overhead space. Push-button control for local open/close; network type is AC, 50/60 Hz.