Siemens 5SL4303-7 — 3A C-curve 3-pole MCB, 10 kA, 400 V
The Siemens 5SL4303-7 is a SENTRON miniature circuit breaker rated 3 A with a C-curve trip characteristic, three poles, and a 10 kA breaking capacity at 400 V AC per both EN 60898 and IEC 60947-2. That 10 kA figure is the interrupting rating the breaker can clear under fault conditions without welding its contacts — it matches the standard fault level for most residential and light-commercial distribution boards. The 3-pole design handles three-phase 400 V AC networks, with a maximum operating voltage of 440 V AC per the datasheet. Frequency range is 50/60 Hz.
The IP20 rating applies only with connected conductors — the busbar and wiring must be in place for the finger-safe protection to hold. Mounting position is any, so vertical or horizontal rail orientation is fine. Sealable design allows padlocking the toggle in the off position for lockout/tagout.