The Siemens 5SL1125-7MB is a SENTRON miniature circuit breaker (MCB) — one pole, C-curve, rated 25 A at 230/400 V AC with a 3 kA breaking capacity per IEC 60947-2.
Form factor and panel fit
Mounts in any position. The IP20 rating is with conductors connected — meaning it's protected against finger contact inside an enclosed distribution board, not for wet or outdoor locations. Installation depth of 70 mm leaves room for cable bending behind the busbar.
The 25 A rating at 230 V single-phase or 400 V multi-phase covers most final subcircuits in residential and light-commercial panels — lighting, GPOs, small HVAC. The 3 kA breaking capacity (IEC 60947-2) is the key constraint: if your available fault current at the panel exceeds 3 kA, you need a higher-rated breaker (like the 5SL series with 6 kA or 10 kA variants).