It carries a MicroLogic 5.0 A electronic trip unit providing LSI protection — long-time overload (L), short-time short-circuit (S), and instantaneous short-circuit (I) — with a 20-minute thermal memory for nuisance-trip avoidance on re-energized loads. Rated 1250 A at 50 °C, it is sized for main feeder or large distribution duty in commercial and industrial switchboards.
This breaker is code H, delivering 70 kA Icu at 415 V AC and 85 kA Icu at 240 V AC per IEC 60947-2. At 690 V AC it still holds 42 kA Icu. The utilization category B rating confirms it is suitable for selectivity (cascading) schemes where the breaker must pass through a higher fault current to a downstream device.
Physical integration into the panel
Fixed-mounted on a backplate, this breaker occupies a 210 mm width, 327 mm height, and 147 mm depth footprint — substantial, so verify gland-plate and bus-bar clearance before layout. Both line and load connections are front-accessed, with a 70 mm connection pitch. The IP40 enclosure (IK07 impact) suits indoor switchgear but not washdown; if the panel sees hose-down cleaning, plan for an upstream enclosure.
What the MicroLogic 5.0 A trip unit gives you
The electronic trip unit provides an ammeter display and four red LEDs for fault indication plus one yellow LED for overload pre-alarm. The LSI protection curve is field-adjustable for long-time pickup and delay, short-time pickup and delay, and instantaneous pickup — no earth-leakage module fitted (specified as 'Without'). The 20-minute thermal memory means if the breaker trips on overload and is reclosed quickly, the trip curve accounts for residual heating, preventing re-trip on a still-warm conductor. This matters for motor or transformer feeders where repetitive starting inrush could otherwise cause nuisance trips.