The Siemens 5SY6605-8 is a 4-pole (3P+N) SENTRON miniature circuit breaker with a D tripping characteristic, rated 0.5 A at 400 V AC. At 0.5 A, this is a low-current branch or control-circuit protector, not a main feeder breaker. The 4-pole construction with switched neutral suits three-phase circuits where you need all poles ganged, common in European industrial panels. Breaking capacity is rated 6 kA per EN 60898 and 30 kA per IEC 60947-2, with a DC rating of 15 kA at 72 V per IEC 60947-2 and 5 kA at AC per UL 1077 / CSA C22.2 No.235. The 30 kA IEC rating gives headroom for high-fault installations — a panel with upstream transformer capacity that could deliver substantial short-circuit current. The 6 kA EN 60898 rating is the standard household/commercial value; the 30 kA figure is what matters for industrial coordination studies.
Mounts via the quick assembly system — the standard DIN-rail clip for SENTRON 5SY6 breakers. Installation depth is 70 mm; total depth with the breaker body is 76 mm. Combined terminals top and bottom simplify busbar or ring-tongue connections.