What this 4-pole C-curve MCB does on the panel
The SENTRON 5SQ2670-2YA10 is a 4-pole miniature circuit breaker (3P+N) with C-curve tripping characteristic, rated 10 A at 400 V AC and 3 kA breaking capacity per EN 60898. The C-curve (5–10× In) handles motor inrush and transformer magnetizing currents cleanly; it won't nuisance-trip on a small pump or contactor coil start. The 4-module-width footprint (4 MW) snaps onto standard DIN rail; the 55 mm installation depth leaves room for cable management in a shallow enclosure.
At 40 °C it derates to 9.5 A; at 50 °C to 9 A; at 60 °C to 8.5 A. That derating curve matters when you're sizing for a continuous load near the limit; a 9 A heater bank at 50 °C ambient is fine, but a 9.5 A load at that same ambient will eventually walk the bimetal.
Pollution degree and overvoltage category
That combination means the clearance and creepage distances are designed for industrial environments where transient overvoltages from upstream switching or lightning coupling are expected.
IP20 and panel integration
IP20 protection (finger-safe terminals, no water ingress protection) — this breaker lives inside a closed enclosure, not on an open wall.