The Schneider Electric LV839316 is a MasterPact MTZ3 drawout circuit breaker rated for 4000 A continuous at 40 °C on a 635 VAC, 50/60 Hz network. It is a 3-pole device with an breaking capacity code, meaning it delivers 200 kA Icu at 254 V AC 60 Hz and 150 kA Icu at 508 V AC 60 Hz per ANSI C37.50 — the interrupting rating that governs its placement in a distribution switchboard. The drawout mounting allows the breaker to be racked out for maintenance without disturbing the bus connections, which is standard for large-frame ANSI gear where uptime and isolation are priorities.
The 4000 A line-rated current sets the maximum continuous load this breaker can carry without derating — sized for a main or large feeder in a 480 V industrial distribution. The integral instantaneous protection trips between 243 and 297 kA, covering bolted faults near the bus. Short-time withstand (Icw) is 100 kA for 0.5 s, which is the rating that matters for selective coordination: downstream breakers can clear a fault while this breaker holds closed, keeping the rest of the plant online. Maximum breaking time is 9 ms, and closing response is 70 ms — both fast enough to limit arc-flash energy in a properly coordinated system. Mechanical durability is 10,000 cycles; electrical durability is 2,800 cycles under ANSI C37.50 — this is a switchgear-class breaker, not a daily-operating contactor, so the cycle count reflects its role as a protective device that opens only on fault or scheduled isolation.
Integration into the switchboard
The LV839316 ships as a drawout unit on a base plate with rails. Panel builders need to account for the 16.8 in depth, 31.07 in width, and 18.8 in height — this is a full-frame breaker that occupies a dedicated cubicle in a metal-enclosed low-voltage switchboard. Connection pitch is 9.06 in (230 mm), which matches the standard bus-bar spacing for ANSI 3-pole drawout gear. The unit comes without a Micrologic trip unit, so the specifying engineer selects and installs the trip unit separately — a common practice when the protection curve (LSIG, LS, or LSI) needs to match the coordination study.