MCB for low-current D-curve protection
The Siemens 5SY6614-8 is a 4-pole (3P+N) miniature circuit breaker from the SENTRON 5SY6 series, rated 0.3 A with a D tripping characteristic. Breaking capacity is 6 kA per EN 60898 for general distribution and 30 kA per IEC 60947-2 for industrial panel duty, so it handles fault levels common in 400 V AC switchgear without cascading upstream. Rated 400 V AC phase-to-phase, with a maximum DC rating of 72 V for control-circuit applications. The 0.3 A rating is uncommon — most MCBs in this frame start at 1 A or higher — so this part fills the niche for protecting low-current branches where a fuse would normally go, but where resettable overcurrent protection and selectivity are required.
IP20 with connected conductors; touch protection is built in. Ambient temperature range -25 to +55 °C operating, -40 to +75 °C storage. Sealable (padlockable) for lockout/tagout procedures. Halogen-free and silicon-free construction suits environments where outgassing must be minimized, such as clean rooms or sealed enclosures.
Rated breaking capacity: 6 kA per EN 60898 (household-type MCB standard), 30 kA per IEC 60947-2 (industrial circuit-breaker standard), and 15 kA at DC per IEC 60947-2. Also carries a 5 kA rating at AC per UL 1077 and CSA C22.2 No.235 for North American supplementary protection applications.