The Siemens 5SY8614-7 is a SENTRON miniature circuit breaker, 4-pole (3P+N), C-characteristic, rated 0.3 A at 400 V AC. Its 70 kA breaking capacity per IEC 60947-2 means it can safely interrupt fault currents up to that level without upstream cascading — a key spec for high-fault panels where selectivity matters. At DC per the same standard it handles 15 kA, and under UL 1077 / CSA C22.2 No.235 it's rated 5 kA.
The C-curve trips between 5 and 10 times rated current — typical for motor and transformer branch circuits where inrush isn't extreme but still above lighting loads. At 0.3 A this is a low-current MCB, not a general-purpose lighting breaker; it's sized for control transformers, contactor coils, or PLC power supplies drawing under 0.3 A. The 4-pole version with switched neutral (3P+N) suits three-phase systems where you want the neutral opened and closed with the phases.
Mounts on DIN rail via the quick assembly system, 4 modular width units (72 mm wide). Installation depth is 70 mm; total depth 76 mm. Any mounting position is allowed, and the IP20 rating (with connected conductors) means it's for enclosed panel use only — not for wet or outdoor locations. The combined terminal top and bottom accept the same conductor range, and the neutral is switched internally (3P+N). Sealable to prevent tampering, halogen-free and silicon-free for environments sensitive to outgassing.