The Siemens 3VA1225-4EF42-0KH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection, carrying 250 A continuously at 40 °C and delivering a 121 kA interrupting capacity at 240 V. The 4-pole design with a shunt trip (STL) release and an auxiliary switch configuration (2 aux + 1 trip alarm HQ) makes it a fit for main or feeder breakers where remote signaling and trip control are needed.
Compared to the smaller-frame 3VA1110-5ED36-0AC0, this 3VA1225-4EF42-0KH0 steps up from a 100 A frame to a 250 A frame and from 3-pole to 4-pole, with a significantly higher interrupting rating (121 kA vs 36 kA at 240 V). The physical footprint grows from 70 x 76 x 130 mm to 70 x 140 x 158 mm, so a panel originally laid out for the 3VA1110 cannot accept this breaker without reworking the busbar and mounting holes.
Mounts on a DIN rail or direct panel via the SENTRON 3VA base plate. The 70 mm depth fits standard 800 mm deep enclosures; the 140 mm width and 158 mm height require a 4-pole breaker cutout. Power loss at rated load is 57 W — account for that in the enclosure thermal budget, especially if the breaker is grouped with other heat sources.