What it is and what it does
The C11N3TM016B is a Schneider Electric ComPacT NSXm thermal-magnetic circuit breaker, 3-pole, rated 16 A at 40 °C, with a breaking capacity of 50 kA at 415 V AC. That 50 kA at 415 V AC means it can safely interrupt a fault current up to that level without welding contacts or cascading upstream — a solid SCCR headroom for most distribution panels. The TM-D trip unit gives you thermal overload protection (inverse-time) and magnetic short-circuit protection (instantaneous), so it covers both branch-circuit and feeder duty in a single device.
Where it fits in the panel
Mounts on a backplate, horizontal or vertical, flat on the back — no DIN-rail adapter needed, though it does occupy 9 module pitches (81 mm wide, 137 mm high, 80 mm deep). The front-facing compression-lug or busbar terminals make wiring straightforward in a gland-plate layout. IP40 means it's protected against tools and wires >1 mm, but not against dust ingress; keep it inside a closed enclosure. Pollution degree 3 per IEC 60664-1, so it's rated for industrial environments where conductive dust or condensation may occur.
What the ratings mean for your decision
The 50 kA at 415 V AC is the headline number — it's the interrupting capacity under short-circuit conditions. For a 16 A breaker, that's a high fault-current rating, meaning it can sit close to a transformer or large motor starter without needing a current-limiting fuse upstream. The 16 A rating at 40 °C is the continuous current; if your ambient runs hotter, derate per the thermal curve. Electrical durability is 20,000 cycles at 440 V at rated current, 10,000 at 440 V at In, and 5,000 at 690 V at In/2 — so it's built for frequent switching, not just backup protection. Mechanical durability is 20,000 cycles. Suitability for isolation is confirmed per IEC 60947-2, so you can use it as a disconnecting means.