25 A B-curve 4-pole MCB for panel protection
It's not the curve for motor starting (that's C or D), but for protecting a 4-wire distribution branch in a panel, this is the standard pick. That's enough headroom for a typical sub-distribution board fed from a 630 kVA transformer.
DIN-rail fit and wiring
Any mounting position is permitted, which simplifies layout in a crowded enclosure. Terminals accept solid or stranded conductors from 0.75 up to 35 mm² — that's a wide range, covering everything from 1.5 mm² control wiring up to 10 mm² feeder tails. Combined top and bottom terminals mean you can bus-bar the line side and still land the load side without extra adapters. IP20 with conductors connected — standard for enclosed panel gear.
Environmental tolerance
That covers most indoor panel environments, including unheated electrical rooms. Humidity tolerance is specified up to 95% at 55 °C, derating to 35% at 75 °C — fine for non-condensing conditions in temperate climates.