What this MCB covers
The Siemens 5SL6263-6BB is a 2-pole SENTRON miniature circuit breaker rated 63 A with a B tripping curve, designed for residential and light commercial distribution boards. It breaks fault currents up to 6 kA per EN 60898 and IEC 60947-2, which means it handles standard domestic and small-building fault levels without cascading upstream — the 6 kA rating is the interrupting capacity, not a continuous rating, so it's sized for the typical service-entrance short-circuit duty. The B curve trips between 3 and 5 times rated current, making it a good fit for resistive and general-purpose loads where you want fast clearing on a short but tolerance for inrush from smaller motors or transformers.
Panel fit and wiring
The 5SL6263-6BB occupies 2 width units (36 mm) on a DIN rail, with a mounting depth of 70 mm and overall depth of 76 mm. Terminal capacity accepts solid or stranded copper from 0.75 to 25 mm², so it handles the full range of 63 A feeder conductors without needing a reducer. Tightening torque is 2.5 to 3 N·m, typical for a 63 A terminal block. It's sealable and carries IP20 with connected conductors — standard for enclosed distribution boards, not for wet locations. Mounting position is any, which helps when you're cramming a board into a tight enclosure corner.