Siemens 5SL4125-6CC — SENTRON 1-pole MCB, B-curve, 25 A
The Siemens 5SL4125-6CC is a SENTRON 5SL series miniature circuit breaker, single-pole, with a B tripping characteristic and a 25 A rated current. Its 10 kA breaking capacity per EN 60898 means it can safely interrupt fault currents up to that level in residential and light commercial distribution boards — the standard rating for final subcircuits in most European installations. The 1-pole, 1-width-unit (18 mm) form factor snaps onto a DIN rail and occupies one slot, so it drops directly into a populated panel without re-spacing adjacent breakers. Rated for 230/400 V AC single-phase and multi-phase operation respectively, with a maximum multi-phase voltage of 440 V AC. The B-curve trips between 3 and 5 times rated current — suited for resistive and general-purpose loads where inrush is moderate, like lighting circuits, socket outlets, and small appliance feeds. Energy limiting class 3 keeps let-through energy low, reducing stress on downstream wiring and equipment during a fault.
Integration and mounting
Mounts in any position on a 35 mm DIN rail per EN 60715. Installation depth is 70 mm, overall depth 76 mm — verify clearance against enclosure door or busbar shroud depth. The 18 mm width (1 width unit) matches the standard modular grid; no special end-plate or spacer needed for adjacent breakers. Terminals accept 0.75 mm² to 25 mm² solid or stranded copper — covers the full range from 1.5 mm² lighting circuits up to 6 mm² feeder tails. IP20 protection with connected conductors; suitable for dry indoor enclosures only. Sealable with a lead seal or adhesive label to prevent unauthorized reset after commissioning.
Environmental and compliance
Halogen-free and silicon-free construction — relevant for panels in clean-room or semiconductor-adjacent environments where outgassing must be minimized. Rated for ambient temperatures up to +55 °C with 95% humidity, and vibration resistance of 50 m/s² at 25 to 150 Hz per IEC 60068-2-6. Overvoltage category 3, pollution degree 2 typical for fixed-installation distribution boards.