What it is and what it does
The Siemens 5SL6216-7CC is a SENTRON miniature circuit breaker (MCB) — a 2-pole, C-curve device rated 16 A at 400 V AC with a 6 kA breaking capacity per EN 60898. That C-curve means it trips between 5× and 10× rated current, so it handles moderate inrush from motor starters or lighting ballasts without nuisance tripping. The 6 kA rating tells you it safely interrupts a fault up to that level under standard residential or light-commercial fault conditions.
Where it goes and how it fits
This MCB snaps onto a standard DIN rail — 2 modular width units (36 mm wide) — and accepts supplementary devices (auxiliary contacts, shunt trips, alarm switches) on the right side. Mounting position is any, so it works in vertical or horizontal panel layouts. The 76 mm depth (70 mm installation depth) leaves clearance for wiring and busbar connections in a standard distribution board.
Thermal derating — the real-world current
Rated 16 A at 30 °C ambient. In a warm enclosure at 40 °C, expect 15.28 A; at 50 °C, 14.53 A; at 55 °C, 14.14 A. If your panel runs hot, size the upstream protection for the derated figure, not the 16 A label.