The Siemens 3VA1225-4EF42-0BH0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current at 40 °C, with a 4-pole configuration and a TM240 thermal-magnetic release. It's the line-protection variant — meaning it's built for feeder and main breaker duty, not motor branch circuit protection. Breaking capacity is the headline here: 121 kA at 240 V AC, 75.6 kA at 415 V, 25 kA at 440 V, and 11.9 kA at 690 V. The TM240 release gives a fixed thermal pickup at 250 A (the rated current) and a magnetic trip that's adjustable via the front dial — typical for coordinating with downstream breakers on a selective scheme.
Fit and panel integration
Dimensions are 158 mm height, 140 mm width, 70 mm depth. The auxiliary contact block is a 2 NO/NC plus one separate trip-alarm switch (HQ type), which gives a dedicated signal for remote fault indication without sharing the auxiliary contact set. An undervoltage release (UVR) is built in — part of the order code's design. The UVR is designated as 3VA9608-0BB11.
Above that it derates linearly: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. Mechanical endurance is rated at 15,000 operations.