What it is and what it does
The Siemens 5SL3225-7 is a SENTRON miniature circuit breaker (MCB) — a 2-pole, C-curve device rated 25 A at 400 V AC, 50/60 Hz. It protects branch circuits against overload and short-circuit in residential and infrastructure panels. The C-curve characteristic (tripping between 5× and 10× In) suits it for general-purpose loads with moderate inrush — lighting, socket outlets, small motor circuits — where the magnetic trip needs to ride through a brief start-up surge without nuisance tripping.
Breaking capacity and selectivity
Rated breaking capacity is 4.5 kA per EN 60898 and 5 kA per IEC 60947-2. The dual rating means the 5SL3225-7 is certified for both the residential MCB standard (EN 60898) and the industrial standard (IEC 60947-2). The 5 kA figure under IEC 60947-2 gives a bit more fault-current headroom for industrial panel applications where the prospective short-circuit current is higher than a typical domestic installation. Overvoltage category III and pollution degree 2 confirm it is rated for fixed-installation use downstream of the utility meter — not for plug-in portable equipment.
Panel fit and integration
Snap-on DIN-rail mounting (implied by the SENTRON form factor) and any mounting position simplify panel layout. Width is 36 mm — 2 modular width units. Depth is 76 mm; installation depth is 70 mm. The IP20 rating applies with connected conductors; the breaker itself is not sealed against dust ingress, so it belongs inside an enclosure. Sealable, halogen-free, and silicon-free — relevant for clean-room or sensitive-environment panels where outgassing or tamper evidence matters. Supplementary devices (auxiliary switches, shunt trips, alarm contacts) can be installed on the side.