Siemens 5SY5114-7KK11 — SENTRON 1-pole C-curve MCB for universal-current and railway applications
The Siemens 5SY5114-7KK11 is a 1-pole miniature circuit breaker from the SENTRON family, designed for universal-current operation (AC/DC) and explicitly built for railway applications. Its C-curve tripping characteristic makes it suitable for protecting circuits with moderate inrush currents — typical for motor starters, contactor coils, and control transformers in industrial panels. The breaker is rated 10 kA breaking capacity per EN 60898 and 15 kA per IEC 60947-2 at DC, with a rated voltage of 400 V AC and 220 V DC (max 250 V DC operating). It occupies a single modular width (18 mm) on DIN rail, mounts in any position, and is sealable for tamper-proof installations.
Breaking capacity and selectivity — what the ratings mean for your panel
The 10 kA rating per EN 60898 is the standard for domestic/commercial MCBs; the 15 kA per IEC 60947-2 at DC gives you headroom in industrial DC control circuits where fault currents can be higher. Energy limitation class 3 means the breaker limits let-through energy to a low level, which protects downstream equipment and reduces arc-flash risk. The C-curve (magnetic trip between 5 and 10 times rated current) avoids nuisance tripping on capacitive or motor-start loads while still clearing short circuits fast. Pollution degree 3 and overvoltage category III confirm it's rated for fixed installations in industrial environments where transient overvoltages are common.
Mounting and wiring — DIN-rail fit and terminal details
The 5SY5114-7KK11 snaps onto standard 35 mm DIN rail via the quick assembly system. At 18 mm wide (1 MW), it leaves room for adjacent breakers or auxiliaries in a crowded panel. Installation depth is 70 mm; overall depth is 76 mm including the actuator. Combined terminals at top and bottom accept both busbar and conductor connections. The supply cord position is AC as required, but DC polarity must be observed — a detail that matters when wiring DC control circuits. The breaker is IP20 with connected conductors, so it's protected against finger contact but not against water ingress; mount inside a suitable enclosure.