The LV839069 is a Schneider Electric MasterPact MTZ2 drawout circuit breaker, 3-pole, rated 800 A at 40 °C. That 800 A line current is the continuous rating in a 104 °F ambient — the number you use for cable and bus sizing, not a peak or short-time figure. The breaking capacity code means it delivers 200 kA Icu at 254 V AC 60 Hz per ANSI C37.50, dropping to 130 kA at 635 V AC 60 Hz. For a buyer matching an existing switchboard spec, the drawout cradle and base-plate-rail mounting (connection pitch 4.5 in) are the mechanical fit check — the 17.5 in width and 16.8 in depth tell you whether it lands in the existing cell without a bucket rework.
What the interrupting ratings mean in practice
At 508 V AC 60 Hz the Icu is 200 kA; at 635 V AC 60 Hz it drops to 130 kA. The rated short-time withstand current (Icw) is 30 kA for 0.5 s per ANSI C37.50, which governs selectivity coordination with downstream breakers during a delayed trip. Integral instantaneous protection is set at 49.5 to 55.5 kA, and the maximum breaking time is 9 ms — fast enough to limit let-through energy on a high-fault bus. Mechanical durability is 12,500 cycles; electrical durability 2,800 cycles under ANSI C37.50 — numbers that matter for a breaker that sees regular switching, not just fault backup.