The Siemens SENTRON 3VA1225-4EF32-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated 250 A continuous at 40 °C, with a TM240 thermal-magnetic overcurrent release. The 121 kA breaking capacity at 240 V (75.6 kA at 415 V, 52.5 kA at 440 V) gives it the interrupting muscle to handle high-fault utility or transformer-fed panels without cascading failure upstream. That keeps it simple and reliable for standard overcurrent protection, but means coordination studies rely on the fixed trip curve.
Current derating and thermal reality
Above that, it derates: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C.
Mechanical fit and auxiliary options
The basic switch supplied is order code 3VA12254EF320AA0, and it accepts up to 3 auxiliary switches (HQ type). No undervoltage release, no shunt trip, no voltage trigger — this is a bare-bones line protection breaker. If you need those accessories, you'll need to add them separately.