The Schneider Electric LV839309 is a Masterpact MTZ3 40 HA automatic switch disconnector, rated 4000 A at 104 °F (40 °C) for distribution duty. It's a 3-pole drawout unit on a chassis mount, controlled via push-button, and built for AC networks at 50/60 Hz.
Breaking capacity and withstand — the real coordination numbers
The LV839309 delivers 65.0 kA Icu at 254 V, 508 V, and 635 V AC (50/60 Hz) with an external relay per ANSI C37.50. That's a flat 65 kA across the common distribution voltages — no derating curve to chase. The rated short-time withstand current [Icw] is also 65.0 kA for 0.5 s per ANSI C37.50, which means it holds through a delayed trip without welding contacts. For a site electrical engineer building a selective coordination study, that Icw match to Icu simplifies the upstream breaker choice — you don't need a bigger gap between the two.
The drawout mechanism and chassis mount mean the LV839309 is designed for a fixed switchgear lineup, not a DIN-rail panel. Depth is 16.8 in (426.8 mm), width 31.07 in (789.1 mm), height 18.8 in (478.1 mm). Connection pitch is 9.06 in (230 mm) — verify busbar spacing against your existing switchgear cubicle before committing the footprint. The drawout cradle stays in the cabinet; the breaker element racks in and out for maintenance without disturbing the line and load connections.