What the ratings mean for fit
The Siemens SENTRON 5SQ2170-0KA50 is a 1-pole miniature circuit breaker (MCB) with a C-curve tripping characteristic, rated 50 A at 240 V AC. The C-curve means it trips between 5 and 10 times rated current — standard for motor and lighting circuits with moderate inrush. The 3 kA breaking capacity per EN 60898 tells you it can safely interrupt a fault current up to that level in a residential or light commercial distribution board; if your available fault current is higher, you need a breaker with a higher interrupting rating or upstream current-limiting protection. Rated for AC and DC voltage (AC/DC type) at 50 Hz. The 55 mm installation depth fits standard SENTRON distribution boards and enclosures. IP20 means it's protected against solid objects larger than 12 mm (fingers) but not against moisture — suitable for dry indoor panel environments only.
Panel integration
Occupies 1 width unit (18 mm) on a DIN rail. The 55 mm depth is shallower than many SENTRON siblings (e.g., 5SY series at 70 mm), which matters when the backplane clearance is tight. No neutral conductor switching — this is a single-pole line-side break only.