63 A B-curve MCB for residential and infrastructure panels
The Siemens 5SL6663-6 is a 4-pole (3P+N) miniature circuit breaker from the SENTRON 5SL6 family, rated 63 A with a B tripping characteristic. Rated for 400 V AC phase-to-phase and 440 V AC maximum in multi-phase operation, with a neutral conductor that is switched (the N pole is not just a solid link). The 63 A rating on a 4-module (72 mm wide) footprint means this breaker fills four width units on a DIN rail — standard for a 3P+N 63 A MCB in European-style panels.
That matches the typical SCCR of a domestic consumer unit. If your distribution board's prospective fault current exceeds 6 kA, you need to step up to a higher-rated series (like the Siemens 5SY with 10 kA or 25 kA). The 63 A rating governs the upstream cable sizing — typically 16 mm² or 25 mm² copper, depending on installation method. Terminals accept solid or stranded conductors from 0.75 mm² up to 25 mm², with a tightening torque of 2.5 to 3 N·m. That 25 mm² upper limit is generous for a 63 A breaker — it allows direct connection of the incoming supply cable without a separate terminal adapter. The screw terminals are touch-protected per the product feature. The storage range is wider at -40 to +75 °C.
For compliance documentation, the SENTRON 5SL6 series is designed to EN 60898 and IEC 60947-2, with overvoltage category 3 and energy limiting class 3. The product is halogen-free and silicon-free, and is rated IP20 (with connected conductors). Touch protection is built in.