It's the replaceable protection element that determines the breaker's overload and short-circuit response — not the breaker frame itself. Rated 25 A at 50 °C, it protects 4 poles in a 4D configuration, meaning all four poles are monitored and the neutral is fully protected at 1 x Ir. The trip unit carries LI protection: thermal L for overload, magnetic I for short-circuit. The instantaneous magnetic pickup is fixed at 300 A, and the long-time thermal pickup is adjustable from 0.7 to 1 x In.
The adjustable long-time pickup (Ir) from 0.7 to 1 x In lets you fine-tune the overload threshold without swapping the trip unit: at 0.7 x In you get a 17.5 A effective setting, at 1.0 x In you get the full 25 A. The fixed instantaneous pickup at 300 A means the magnetic trip clears short-circuits above that level — about 12 x In — which is typical for distribution protection where you want some selectivity downstream. The 4D protected poles with neutral protection at 1 x Ir means the neutral pole is fully rated and monitored — not just switched. This matters for 4-wire systems where the neutral carries load and a fault on any phase needs to be cleared. The fixed long-time delay (tr) gives a 120...400 s band at 1.5 x In and 15 s at 6 x Ir — that's a standard thermal curve for distribution, not for motor starting. If you're protecting a motor load, you'd want a different trip unit with a longer delay.