What the 400 A and MicroLogic 2.3 mean for your panel
The MGP4003TX is a Schneider Electric PowerPacT 4 panel-mounted circuit breaker rated 400 A at 40 °C with a MicroLogic 2.3 electronic trip unit. The MicroLogic 2.3 gives you LSoI protection: L (thermal overload) with a 20-minute thermal memory before and after tripping, So (short-time short-circuit with fixed delay), and I (instantaneous short-circuit). This combination means you get selective coordination downstream — the So delay lets a fault on a branch clear before the main trips, keeping the rest of the panel live.
Integration into the panel — mounting and environment
The 3-pole form factor takes up 4 module spaces at 35 mm per module.
Electrical durability and what it tells you
Rated for 12,000 electrical cycles at 440 V at half rated current (In/2), and 6,000 cycles at full rated current (In). Mechanical durability is 15,000 cycles. These numbers matter for applications with frequent switching — if your panel cycles the main breaker daily, you'll want to compare against your expected service life. For a typical distribution board that sees a few operations per year, this is more than adequate.
Certified to BS EN 60947-2, the standard for low-voltage switchgear and controlgear circuit breakers. IK07 impact resistance means it survives a 2 joule impact — typical for panel-mounted gear.