The Siemens 3VA1225-4GF42-0AF0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection, 4-pole, with a continuous current of 250 A at 40 °C. The TM240 thermal-magnetic release handles overloads and short-circuits; the interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 440 V — figures that define where this breaker can be applied without cascading upstream.
Ratings and what they mean for your panel
At 250 A continuous, this MCCB is sized for large feeders or main disconnects in distribution panels. The interrupting ratings across voltage levels tell you the maximum fault current it can safely clear: 121 kA at 240 V suits high-fault industrial services; at 415 V it still handles 75.6 kA, and at 690 V it drops to 11.9 kA — so for a 690 V system, verify your available fault current stays under that threshold. Thermal derating is published: it holds 250 A up to 50 °C, then steps down to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If your panel ambient runs hot, use the 60 °C or 70 °C row for sizing. Rated insulation voltage is 800 V, and the breaker includes a trip indicator plus one auxiliary switch and one trip alarm switch (HQ design) for remote status monitoring. Power loss at rated current is 57 W — factor that into enclosure thermal calculations.