Integrator note — MTZ3 50 H3 frame
The LV839030 is a fixed-mount MasterPact MTZ3 circuit breaker, 3-pole, rated 5000 A at 104 °F (40 °C). H3 breaking capacity delivers 100 kA Icu at 254 VAC, 100 kA at 508 VAC, and 85 kA at 635 VAC per ANSI C37.50. No Micrologic trip unit is included — order separately to match the protection curve to your load.
Breaking capacity — what H3 means for your fault duty
H3 is the highest standard breaking capacity tier for this frame. The Icw (short-time withstand) is 85 kA for 0.5 s, which governs selective coordination with downstream breakers.
Integration — fixed-mount footprint on base plate rails
Mounts on a base plate with rails. Overall dimensions: 30.2 in wide, 13.9 in high, 11.7 in deep. Connection pitch is 9.06 in (230 mm) between phases. The fixed-mount version is intended for bolted connections in a switchgear lineup — no draw-out cradle. Plan for a 4000 A CT set if the trip unit requires external sensing.
Durability and closing times — coordination data
Mechanical endurance is 12,500 cycles; electrical endurance under load is 2,800 cycles per ANSI C37.50. Maximum breaking time is 25–30 ms, closing response is 70 ms max. Integral instantaneous protection is set at 171–209 kA. Rated making and breaking capacity is 170 kA. These figures drive selectivity studies and arc-flash incident energy calculations.