The Siemens 5SY7416-8CC is a 4-pole SENTRON miniature circuit breaker (MCB) with a D tripping characteristic, rated 16 A at 35 °C and 440 V AC. It's built for the mechanical engineering and industrial sector, where high inrush currents from motor loads or transformers are the norm — the D-curve holds fast against those startup surges without nuisance tripping on the branch circuit. That's a solid number for a panel-fed motor control center — it won't cascade upstream on a hard bolted fault.
Real-world fit and derating
It's 4 modular width units wide (72 mm), so it takes up four 18 mm slots in the enclosure. The 16 A rating is at 35 °C ambient. Out here in a warm cabinet — say 50 °C — it derates to 13.55 A. At 55 °C you're looking at 12.86 A. That's the number that governs the real wire-up, not the 35 °C sticker. Plan your load accordingly if the panel runs hot. Humidity tolerance is spelled out: max 95% up to 55 °C, dropping to 55% at 70 °C and 35% at 75 °C. That's a wide operating range, but if the panel lives near a washdown zone, keep the enclosure sealed — IP20 with connected conductors means no water jets.
What the D-curve means for your load
For a 16 A MCB, that's 160 to 320 A instantaneous trip threshold. The sealable feature lets you lock the toggle position to prevent unauthorized reset after a trip.