The 10 kA interrupting rating at 240 VAC tells you it can safely clear a fault up to 10,000 A without welding contacts or venting gas into the panel; that's enough for most commercial and light industrial distribution boards, but if your available fault current is higher you'll need a current-limiting upstream device or a higher-rated breaker like the S803S series.
The S400 family shares the same 3-module width (about 54 mm) as most ABB compact MCBs, so it swaps into existing S200 or S500 panels without re-drilling the rail. Rated 240 VAC line-to-line, which covers most single-phase and three-phase 240 V systems; for 400 VAC three-phase applications you'd need the 400 V rated variant in the same family.