What this MCB is and what it does
The Siemens SENTRON 5SY4225-7CC11 is a 2-pole miniature circuit breaker rated 25 A with a C tripping characteristic, designed for AC circuits up to 400 V. It interrupts fault currents up to 10 kA per EN 60898, which means it clears short circuits up to that level without damage to downstream equipment — the standard rating for most industrial distribution boards and sub-panels. The C-curve (tripping between 5 and 10 times rated current) suits it for motor circuits, transformers, and lighting banks where inrush is moderate — not the steep surge of a large drive, but more than a resistive heater load. Pollution degree 3 and overvoltage category III confirm it for fixed installations inside an enclosure, not for outdoor or wet locations.
Mounting and panel fit
Snaps onto standard DIN rail via the quick assembly system, occupying 2 modular width units (36 mm). The 76 mm depth and 70 mm installation depth mean it sits flush with the front of a 100 mm deep enclosure — no extra clearance needed behind the rail. Mounting position is unrestricted, so it works in vertical, horizontal, or inverted panels. Combined terminals top and bottom accept both busbar and cable; touch protection is built in. Rated IP20 with connected conductors — fine for a closed panel, not for washdown zones. The sealable design lets a panel builder lock the toggle position after commissioning.
Environmental and compliance
Designed for railway applications (per the product designation) and mechanical engineering/industry suitability. Halogen-free and silicon-free construction, which matters for clean-room or corrosive-environment installations where outgassing must be minimised.