What it is and what it does
The Siemens SENTRON 5SL6204-7CC is a 2-pole miniature circuit breaker rated 4 A with a C tripping characteristic, designed for 400 V AC residential and infrastructure branch circuits. Its 6 kA breaking capacity per EN 60898 handles typical domestic fault levels without cascading upstream.
Ratings that drive the fit
C-curve means the magnetic trip threshold sits at 5–10× rated current — good for moderate inrush loads like lighting banks or small transformers. The 4 A rating limits it to low-current final subcircuits; on a 400 V three-phase panel, each pole sees 230 V line-to-neutral. The 6 kA SCCR at 400 V means it safely clears faults up to that level, which is the standard domestic and light commercial requirement across Europe. Energy limitation class 3 keeps let-through energy low, protecting downstream equipment.
Where it fits physically
Occupies 2 modular width units (36 mm total) on a standard DIN rail, with a 76 mm depth that leaves room in shallow enclosures. Mounts in any position; the IP20 rating with connected conductors means it's for indoor panels only. Accepts supplementary devices (auxiliary contacts, shunt trips) for remote status or emergency-off functions.