The SENTRON 5SQ2370-0KA63 is a 3-pole miniature circuit breaker (MCB) from the 5SQ family, rated 63 A at 400 V AC with a C tripping characteristic. Rated for AC and DC supply voltage (AC/DC type), so it can also serve DC branch circuits within its voltage limits — check the DC voltage rating curve for your specific application. The 55 mm installation depth and 3 width units (roughly 54 mm) fit standard DIN-rail enclosures;
The closest sibling in the same 5SQ family is the 5SQ2370-2YA04 — identical poles, voltage, breaking capacity, and footprint, but rated 4 A instead of 63 A. If your BOM called for the 4 A version and you need the 63 A, this part is a direct mechanical swap: same 55 mm depth, same 3 width units, same IP20, same DIN-rail clip. No rewiring needed at the panel level — just confirm the load current matches the new rating.
Integration note
Snap-on DIN-rail mount, 3-pole, no neutral switching. Overvoltage category 3 and energy limiting class 3 — suitable for fixed-installation distribution boards with standard surge coordination. Verify the upstream short-circuit capacity is coordinated at 3 kA or less at the point of installation.