What it is and what it does
The Siemens 5SY4116-8CC is a SENTRON miniature circuit breaker (MCB) with a single pole, D tripping characteristic, and a rated current of 16 A at AC. It interrupts fault currents up to 10 kA per EN 60898, which covers the majority of industrial panel secondary-side faults. The D curve means it tolerates the high inrush of motor starters and power supplies without nuisance tripping — the magnetic trip threshold is 10 to 20 times rated current, so it's the right choice for loads with a heavy inductive kick.
Panel fit and mounting
Occupies one modular width unit (18 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. The quick-assembly system clips onto the rail without tools; mounting position is any orientation. Combined terminals top and bottom accept the same conductor range, which simplifies wiring — no need to swap incoming/outgoing lug styles. IP20 with connected conductors, so it's a standard panel-mount device; the sealable option (yes) allows a lead seal for tamper-evident installations.
Derating and environmental limits
Rated 16 A at 35 °C ambient; at 40 °C it's 14.7 A, at 45 °C it's 14 A, at 50 °C it's 13.26 A, and at 55 °C it's 12.5 A. If the panel runs hot — common in a crowded enclosure — use the 40 °C or 50 °C figure for your continuous load calculation, not the 35 °C number. Operating ambient range is -40 to 75 °C, with humidity limits of 95% up to 55 °C, 55% up to 70 °C, and 35% up to 75 °C. Pollution degree 3 (conductive or dry non-conductive pollution that becomes conductive due to condensation) is the rated environment, which covers most industrial control rooms and factory floors.