The LV839299 is a Schneider Electric MasterPact MTZ3 drawout circuit breaker, 3-pole, rated 4000 A at 40 °C, with H breaking capacity. It is a UL 489 listed device for protection of feeders and large loads in industrial switchgear — think main incoming breakers in mining substations, mill distribution centers, or large motor control centers where the fault current potential is high and the gear is expected to take a beating. Rated interrupting capacity hits 100 kA Icu at 240 V AC and 480 V AC, and 85 kA Icu at 600 V AC — numbers that put it squarely in the heavy industrial class. Short-time withstand (Icw) is 85 kA for 0.5 s per UL 489, meaning it can ride through a delayed trip coordination sequence without failing.
Drawout mounting and panel fit
Drawout chassis mounts on base plate rails. The breaker itself pulls out for inspection or replacement without disturbing the main bus connections — a standard requirement in mining and heavy process plants where downtime is measured in dollars per minute. Overall dimensions: 31.07 in wide, 18.8 in tall, 16.8 in deep. Connection pitch is 9.06 in (230 mm). This is not a snap-on DIN rail breaker. It goes into a dedicated drawout cradle in a switchgear lineup. Plan the panel depth and door swing accordingly — 16.8 in depth plus the cradle and rear bus work adds up fast.
Above that temperature, derate per the manufacturer's curve. Mechanical durability is 5000 cycles (open-close operations) and electrical durability is 1000 cycles under load per ANSI C37.50. For a main breaker that operates a few times a year, that's decades of service. Maximum breaking time is 25 to 30 ms — fast enough to limit arc flash energy in a coordinated system. Integral instantaneous protection trips between 153 and 187 kA — that is the magnetic-only short-circuit pickup range, not adjustable. For adjustable protection, a Micrologic trip unit is needed (not included with this order code).