What this MCCB is for
The 800 V rated insulation voltage suits it for 400 V and 690 V line-to-line systems, though the interrupting capacity at 690 V drops to 3.7 kA, so it's best applied at 415 V or below where it delivers 242 kA breaking capacity.
It's a step up from thermal-magnetic releases for selectivity coordination — you can dial in the long-time pickup and delay, short-time pickup and delay, and instantaneous pickup. That matters when you're cascading breakers downstream and need the upstream device to ride through a fault on a branch without tripping the main. No undervoltage release and no ground-fault monitoring are built in; those are add-on accessories if your application requires them.