The Siemens 5SL6125-7CC is a SENTRON miniature circuit breaker — a 1-pole, C-curve device rated 25 A with a 6 kA breaking capacity per EN 60898. It sits in a single modular-width slot (18 mm) on the DIN rail, 76 mm deep, and accepts supplementary devices (shunt trip, auxiliary contacts) for remote status or emergency-off integration.
Rated for the panel environment
Mounting position is unrestricted — the breaker can be installed horizontally, vertically, or flat against the backplane without derating the 25 A rating.
Voltage and breaking capacity — the limits that matter
Rated 400 V AC for multi-phase operation, maximum 440 V AC. Single-phase branch circuits are rated 250 V AC. If your panel feeds from a transformer with higher available fault current, you need a breaker with a higher SCCR (the 5SL4 series with 10 kA, for instance). DC rating tops out at 72 V, so this is an AC-only device for standard branch-circuit protection.