The Siemens 3VA2510-5KQ32-0AJ0 is a 3-pole SENTRON molded case circuit breaker rated for 1000 A continuous current at 40 °C through 55 °C, with a slight derating curve above that — 955 A at 60 °C, 885 A at 65 °C, 815 A at 70 °C. That means you can run it at full nameplate in most ventilated enclosures; only push the derating if the panel ambient climbs above 55 °C. Breaking capacity is the headline number for a main breaker: 187 kA at 240 V, 121 kA at 415 V, 53 kA at 690 V. Those are high-interrupting ratings — enough for transformer-secondaries or large motor-control centers where fault current can hit 100 kA+. The 415 V figure (121 kA) is the one most panel builders will check against their utility transformer impedance; it clears a 100 kA fault with headroom. The ETU860 electronic trip unit gives you adjustable long-time (tr 0.5–25 s), short-time (tsd 0.05–0.5 s), and instantaneous pickup (Ir adjustable up to 1000 A). That means you can shape the curve for selective coordination downstream — a real advantage over fixed-trip thermal-magnetic breakers when you need to keep a fault from taking out the whole MCC.
Mounting and integration — fits a standard MCCB footprint
Dimensions: 320 mm high, 210 mm wide, 120 mm deep. IP40 on the front. Rated insulation voltage 800 V. Maximum power loss 123 W.