The Siemens 5SL3663-6 is a 4-pole (3P+N) miniature circuit breaker from the SENTRON 5SL series, rated 63 A at 400 V AC with a B-curve tripping characteristic. The neutral pole is switched (3P+N), which is required in some regional distribution boards to isolate the neutral on a fault. Terminal capacity accepts solid or stranded conductors from 0.75 to 25 mm², with a tightening torque of 2.5 to 3 N·m — enough for the 63 A feed cable. IP20 with conductors connected; no washdown rating, so it stays inside the enclosure.
How it compares to nearby siblings — 5SL3625-7MB and 5SL3640-7MB
The 5SL3663-6 is the 63 A, 4-pole, B-curve variant. The closest peer in the same form factor is the 5SL3640-7MB (40 A, 4-pole, B-curve) — same footprint, same breaking capacity, same terminal range. The 5SL3625-7MB is a 25 A, 4-pole, B-curve. If your panel was wired for a 25 A or 40 A 5SL3, the 5SL3663-6 drops into the same DIN slot and uses the same wiring (0.75–25 mm² terminals), but the higher current rating means the upstream protective device and cable must be rated for 63 A. No rewiring of the MCB itself is needed; just confirm the branch circuit can handle the increase.
Integration notes — DIN rail, terminal torque, ambient limits
Snap-on DIN rail mount, any orientation. The sealable feature allows a lockout tag to be fitted.