Siemens SENTRON 5SY4105-7CC — 1-pole C-curve MCB, 0.5 A, 10 kA
The Siemens SENTRON 5SY4105-7CC is a 1-pole miniature circuit breaker with a C tripping characteristic, rated 0.5 A at 35 °C and 440 V AC maximum.
The 0.5 A rating at 35 °C is the nominal current; above that ambient, the breaker derates linearly — 0.46 A at 40 °C, 0.44 A at 45 °C, 0.41 A at 50 °C, and 0.39 A at 55 °C. If your enclosure runs warm, size the load below the derated value, not the 35 °C number. Mounting position is any, so vertical or horizontal rail orientation works. IP20 with connected conductors is the protection class — suitable for enclosed panels, not for wet washdown zones.
The 5SY4105-7CC is an active, current-production part. No phase-out or replacement notice is on record.