The Siemens SENTRON 5SL4525-8 is a 2-module (36 mm wide) miniature circuit breaker with a D tripping characteristic, rated 25 A at 230 V AC, 1P+N configuration, and a 10 kA breaking capacity per EN 60898 and IEC 60947-2. The D curve means it tolerates high inrush currents — think motor starts, transformer energization, or welder loads — without nuisance tripping, then clears hard faults fast.
Compared to the 5SL4120-7CC (B curve, 20 A, 1P+N), this 5SL4525-8 swaps to a D curve and a higher 25 A rating. The B curve trips at 3–5× In, suited for resistive or light inductive loads; the D curve trips at 10–20× In, so it's the right choice where the start-up surge would pop a B-curve breaker. Physical footprint is identical — 2 width units, same 76 mm depth — so a panel designed for the 5SL4120-7CC accepts this unit without rewiring.
Snaps onto standard DIN rail in any mounting position. Terminal capacity accepts solid or stranded copper from 0.75 to 25 mm²; tighten to 2.5–3 N·m. The neutral pole switches internally (1P+N), so no separate neutral bar needed for the protected circuit. Ambient range runs –25 to +55 °C, storage down to –40 °C.