The Siemens 5SY7140-7CC is a SENTRON miniature circuit breaker, 1-pole, rated 40 A with a C tripping characteristic. It's built for 400 V AC circuits and carries a 25 kA breaking capacity per IEC 60947-2 — that's the fault-clearing rating that matters for panel coordination in industrial distribution. The C curve means it handles moderate inrush from motor starters or transformers without nuisance tripping, so it's a common choice on control transformer secondaries or mixed-load lighting panels out here in the grease.
Snaps onto DIN rail via the quick-assembly system, one modular width (18 mm). Mounts in any position, which helps when you're shoehorning it into a crowded enclosure. Depth is 76 mm with a 70 mm installation depth behind the panel — that's shallow enough for most wall-mount boxes. IP20 with conductors connected, so it's panel-internal only; no washdown exposure. Terminal is combined top and bottom, touch-protected, and accepts the standard screwdriver for panel wiring.
Rated for 50/60 Hz, overvoltage category III, pollution degree 3 — that's the industrial environment rating, meaning it's designed for fixed installations where conductive pollution is possible. UL 1077 and CSA C22.2 No. 235 recognized at 5 kA, so it's accepted in North American panels as a supplementary protector. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz — tough enough for the route.