What this MCB is and where it fits
The Siemens 5SY6514-7CC is a SENTRON miniature circuit breaker with a 0.3 A rated current and C tripping characteristic, designed for protecting branch circuits in industrial control panels. Its 2-pole (1P+N) configuration switches both phase and neutral, making it suitable for single-phase AC loads up to 250 V at 50/60 Hz. Rated breaking capacity is 6 kA per EN 60898 and 5 kA per UL 1077 / CSA C22.2 No.235, so it handles fault currents up to those levels without cascading upstream. The C-curve trips at 5–10× rated current, which means it handles moderate inrush from small transformers or capacitive loads without nuisance tripping.
Panel integration and mounting
Snaps onto DIN rail via the quick assembly system; mounting position is any, so it works upright, sideways, or inverted in a crowded enclosure. Occupies 2 modular width units (36 mm wide), with a 70 mm installation depth and 76 mm overall depth — fits standard distribution boards without oversize enclosures. Combined terminal at both top and bottom accepts wiring without separate busbar connectors. Neutral conductor switching is built in, so no external neutral link is needed for the switched neutral pole. IP20 with connected conductors; keep the panel door closed during operation.
Thermal derating and environmental limits
Rated 0.3 A at 35 °C, but the current must be derated as ambient temperature rises: 0.28 A at 40 °C, 0.26 A at 45 °C, 0.25 A at 50 °C, and 0.23 A at 55 °C. If the panel runs hot (say, 50 °C internal), size the circuit for 0.25 A continuous, not the nameplate 0.3 A. Operating range is -40 to 75 °C, with humidity limits of 95% up to 55 °C, tapering to 35% at 75 °C. Pollution degree 3 and overvoltage category III — the breaker is rated for industrial environments with conductive pollution and transient overvoltages up to 4 kV. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz, so it holds up on machinery near motors or conveyors.
Lifecycle and compliance
Rated for mechanical engineering and industry applications per the manufacturer's suitability listing. Compliance documentation (RoHS, REACH, UL, IEC) is typically included with the shipment; the UL 1077 listing covers North American acceptance, and EN 60898 covers the European market.