The Siemens 3VA1125-6EF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection, carrying a 25 A continuous current at 40 °C and a 4-pole configuration.
The interrupting rating hits 220 kA at 240 V, dropping to 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V or 690 V. That 220 kA figure at 240 V is the headline — it tells you this breaker can safely clear a fault up to that level on a 240 VAC line without rupturing or cascading upstream. For a 480 V panel the relevant number is the 121 kA at 440 V, which still covers most high-fault installations.
Thermal derating curve — the real continuous current
Rated 25 A from 40 °C through 50 °C (–), then steps down: 24 A at 55 °C and 60 °C, 23 A at 65 °C and 70 °C. The maximum power loss is 8.5 W, which is modest for a 4-pole MCCB; it won't drive much internal heating beyond the ambient.
Dimensions are 70 mm deep, 101.6 mm wide, 130 mm tall. The 101.6 mm width — exactly 4 inches — is the standard footprint for a 4-pole MCCB on a DIN rail or panel-mount base. The 70 mm depth leaves room behind a 200 mm deep enclosure door with clearance for wiring.