The LV839028 is a MasterPact MTZ3 4000 A fixed-mount circuit breaker, 4-pole, with H3 breaking capacity. It's the frame and poles only — no Micrologic trip unit included, so you select and install the trip unit separately to match your protection curve. The H3 breaking capacity code means it delivers 100 kA Icu at 254 V AC and 508 V AC, and 85 kA Icu at 635 V AC per ANSI C37.50. Rated short-time withstand current (Icw) is 85 kA for 0.5 s per ANSI C37.50, which tells you how much fault current the breaker can carry without damage during a delayed trip — important for selective coordination schemes. Integral instant protection trips between 171 and 209 kA — that's the magnetic-only instantaneous pickup range built into the breaker frame, acting as a backup to the trip unit. Mechanical durability is 12,500 cycles, electrical durability 2,800 cycles per ANSI C37.50. For a 4000 A frame that's typical for main breaker duty — not a switching device for frequent load making/breaking.
Fixed mount on a base plate with rails. Neutral position is left. Connection pitch is 9.06 in (230 mm). Overall dimensions: width 39.2 in (996.3 mm), height 13.9 in (352.2 mm), depth 11.7 in (297.7 mm). This is a large-frame breaker — plan your enclosure depth and bus bar routing accordingly. The 4000 A rating is at 104 °F (40 °C) ambient — derate if your switchroom runs hotter.
The LV839028 is the fixed-mount, 4-pole, 4000 A frame with H3 breaking capacity, without trip unit. If you need a different breaking capacity (H1, H2) or a drawout version, those are separate order codes in the MTZ3 family.