What this MCB is and where it fits
The Siemens 5SY4302-6CC is a SENTRON miniature circuit breaker — a 3-pole, B-curve unit rated 2 A at AC with a 10 kA breaking capacity per EN 60898. It's designed for DIN-rail mounting in distribution boards and control panels, protecting branch circuits against overload and short-circuit in commercial and industrial installations. The B-curve characteristic (3–5× In) makes it a good fit for resistive and general-purpose loads where inrush is moderate — lighting, small transformers, or control circuits.
Key ratings — what they mean for your panel
Rated current is 2 A at 35 °C, derated to 1.91 A at 40 °C and 1.75 A at 55 °C — so if your enclosure runs warm, factor the thermal derating into your load budget. The 10 kA breaking capacity at 440 V AC (multi-phase operation) is the maximum fault current this breaker can safely interrupt; that's sufficient for most secondary distribution panels but should be checked against the available fault current at the installation point. Overvoltage category III means it's rated for fixed-installation use downstream of the main service entrance. The 50/60 Hz rating covers both standard line frequencies.
Mounting and integration notes
Occupies 3 modular width units (54 mm total) on a DIN rail. Depth is 76 mm, installation depth 70 mm — verify clearance in your enclosure before committing. Mounting position is any, so vertical or horizontal rail orientation works. Combined terminals top and bottom accept conductors for straightforward daisy-chaining. IP20 with connected conductors — suitable for dry indoor panels only, not washdown or outdoor locations.