The LV838921 is a Schneider Electric MasterPact MTZ2 drawout circuit breaker, 3-pole, rated 1600 A at 104 °F (40 °C) with LF breaking capacity — meaning 200 kA Icu at 240 V AC, 150 kA Icu at 480 V AC, and 100 kA Icu at 600 V AC per UL 489. That's a serious main or feeder breaker for a 600 V class switchboard, sized to handle a 1600 A bus without cascading upstream. The drawout chassis lets you rack the breaker in and out for maintenance or swap without disturbing the bus connections — standard for large-frame power breakers in industrial and commercial distribution.
The integral instant protection trips between 49.5 and 55.5 kA — that's the magnetic-only short-circuit pickup range, set at the factory for this LF code. Maximum breaking time is 9 ms; closing response is 70 ms. Physical footprint: 17.5 in wide, 17.3 in tall, 16.8 in deep — that's the drawout cassette envelope. Mounting is on base plate rails with a 4.5 in (115 mm) connection pitch. Network frequency is 50/60 Hz.