What this MCCB is rated for
Its continuous current rating holds 800 A up to 50 °C ambient, then derates to 780 A at 55 °C, 761 A at 60 °C, 741 A at 65 °C, and 722 A at 70 °C — so if your panel runs hot, the actual trip threshold drops, and you need to account for that in your load calcs, not just the nameplate 800 A. Interrupting capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 52.5 kA at 690 V — that 187 kA at 240 V covers high-fault industrial services (like a transformer secondary) where fault current can exceed 100 kA, so this breaker won't vent or weld closed on a bolted fault.
Dimensions are 320 mm high, 210 mm wide, 120 mm deep — that 120 mm depth is the key number for enclosure depth clearance; it's a standard MCCB footprint, not a compact frame, so it needs a full-depth back panel or a deep gland plate. Maximum power loss is 242.5 W — that's the heat it dumps into the enclosure at full rated current. In a sealed panel, that heat needs to be vented or the internal ambient will rise above the 50 °C derating knee. If you're stacking multiple breakers, sum their losses and check the enclosure's thermal dissipation rating.