What the ratings mean for fit
The Siemens SENTRON 5SL4640-6 is a 3P+N miniature circuit breaker rated 40 A with a B tripping characteristic, breaking 10 kA at 400 V AC per both EN 60898 and IEC 60947-2. The B curve means it trips between 3 and 5 times rated current — suited for resistive and general-purpose loads in residential and infrastructure panels where inrush is low. The 10 kA SCCR at 400 V tells you this breaker can safely interrupt a fault up to that level without upstream cascading; it's the standard rating for most distribution boards in that voltage class. Four modular width units (72 mm) on a DIN rail, with any mounting position allowed. The 76 mm depth plus 70 mm installation depth fits standard distribution board enclosures. IP20 with connected conductors — protected against finger contact once wired, but not against moisture; keep it inside a closed panel. Halogen-free and silicon-free construction matters if this breaker sits in a ventilated enclosure near sensitive electronics — no corrosive off-gassing during a fault. Sealable per the spec, so a utility or facility manager can lock the handle position after commissioning.
Panel integration notes
Snap-on DIN rail mount, any orientation. The 72 mm width (4 MWU) occupies four standard module positions. Supplementary devices can be installed on the right side. Power loss is 3.4 W per pole at rated current.