Siemens 5SY7102-8 — SENTRON D-curve MCB, 1-pole
The Siemens 5SY7102-8 is a current-production SENTRON miniature circuit breaker with a D tripping characteristic, designed for one-pole protection in industrial control panels and distribution boards. It carries dual-standard breaking capacities: 15 kA per EN 60898-1 and 50 kA per IEC 60947-2, with a UL 1077 listing at 5 kA — giving you the SCCR headroom to coordinate downstream without cascading upstream.
What the ratings mean for fit
The D-curve (10–20× In magnetic trip) is the right choice for loads with high inrush — motor starters, transformers, solenoid banks — where a B or C curve would nuisance-trip on startup. The 15 kA EN 60898 rating covers residential and light commercial distribution; the 50 kA IEC 60947-2 rating is what matters for industrial panel SCCR calculations. At 400 V AC rated voltage and 60 V DC, this pole handles the common three-phase and control-circuit voltages. The 18 mm width (1 modular unit) means it occupies a single DIN-rail position, so a 12-pole distribution board fits 12 of these without crowding. Rated for pollution degree 3 and overvoltage category III, it is suited for fixed installations inside enclosures where conductive contamination is possible — typical for machine control panels and industrial switchgear. The IP20 rating (with connected conductors) means it is protected against finger contact but not against moisture; mount it inside a cabinet rated for the environment.
Panel integration and mounting
Snap-on mounting to 35 mm DIN rail per EN 60715, any orientation. The quick-assembly system allows ganging multiple poles via the combined top and bottom terminals — no separate busbar required for multi-pole configurations. Installation depth is 70 mm behind the panel surface; overall depth is 76 mm including the front projection. The sealable design (provision for a lead seal or lockout tag) supports lockout/tagout procedures during maintenance.
Environmental and compliance
Halogen-free and silicon-free construction — relevant for clean-room or high-reliability environments where outgassing could contaminate optics or contacts. Operating temperature range -40 °C to +75 °C, with humidity derating above 55 °C (max 95% RH at 55 °C, tapering to 35% at 75 °C). Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz. Compliance documentation (RoHS, REACH, UL, IEC) is available from the manufacturer.