Line-down fit check — 25 A, C-curve, 4-pole
ABB 2CDS253103R0254 is a 4-pole miniature circuit breaker from the System pro M compact S200 series, rated 25 A with a C tripping characteristic. The C-curve means it trips between 5× and 10× rated current — standard for inductive and motor-start loads where inrush is higher than a resistive heater but lower than a transformer bank. Rated short-circuit breaking capacity Icn is 6 kA per IEC 60898, with an ultimate Icu of 20 kA per IEC 60947-2. The Icu figure tells you the breaker can safely clear a fault up to 20 kA once — the Icn is the service rating for repeated operation. For a distribution board fed from a transformer with a prospective short-circuit current under 6 kA, this breaker holds up across multiple faults without needing replacement after every trip.
What the 25 A and C-curve mean for a panel builder
The 25 A rating with a C-curve is sized for general lighting and socket-outlet circuits in commercial or light-industrial panels, or for motor branch circuits where the starting surge stays within 5–10× In. Rated insulation voltage is 440 V — the breaker fits three-phase 400 V systems with margin. Overvoltage category III means it's rated for fixed-installation distribution boards, not for equipment-level protection. Mounts on a DIN rail — snaps into the standard 35 mm profile. The bi-directional cylinder-lift terminals accept both busbar and cable entry from either side, and the tightening torque max of 2.8 Nm is typical for 25 A terminals: a standard screwdriver with a torque-limiting handle avoids over-torque that cracks the housing.
IP rating and enclosure fit
Rated IP20 on the front face — protected against finger contact but not water ingress. IP40 applies to the enclosure sides when the breaker is mounted in a distribution board. This is the standard rating for indoor DIN-rail MCBs in a closed panel; no special sealing needed for a clean, dry electrical room.