What this MCB is and what it does
The Siemens 5SY7363-7 is a 3-pole miniature circuit breaker from the SENTRON family, designed for branch-circuit protection in industrial control panels and distribution boards. Its C tripping characteristic (magnetic trip between 5 and 10 times rated current) suits it for moderate inrush loads like motor starters, contactor coils, and small transformers where the start-up current exceeds a B-curve's tolerance but doesn't need the higher threshold of a D-curve. Rated 400 V AC at 50/60 Hz, it carries a breaking capacity of 15 kA per EN 60898-1 and 20 kA per IEC 60947-2 — enough headroom for most industrial service-entrance or sub-distribution panels where the prospective fault current sits in that range. The DC rating is 60 V (15 kA per IEC 60947-2), so it also handles DC control circuits fed from a 48 V or 60 V supply.
Panel fit and mounting
Occupies 3 modular width units (54 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. The quick-assembly fastening system snaps onto the rail without tools; mounting position is any orientation. IP20 with connected conductors means it's protected against finger contact but not washdown — standard for enclosed panel mounting. Combined terminals top and bottom accept supply from either end, and the neutral conductor is not switched (the breaker is 3-pole only). Sealable design allows the installer to lock the toggle position after commissioning — useful for lockout/tagout compliance on a dedicated machine feed.
Standards and compliance
Dual-rated to IEC/EN 60898-1 (15 kA) and IEC/EN 60947-2 (20 kA), plus UL 1077 (5 kA at 400 VAC) and CSA C22.2 No. 235. Overvoltage category III, pollution degree 3 — suitable for fixed-installation distribution boards where the breaker sees transient overvoltages from the mains. Halogen-free and silicon-free construction, energy limitation class 3. Ambient temperature range -40 °C to 75 °C, with derating on humidity: max 95% RH at 55 °C, tapering to 35% RH at 75 °C. That covers most indoor industrial environments including unheated warehouses and enclosed panel interiors near heat sources.