What this MCCB delivers on the line
The Siemens 3VA4125-4ED34-0AA0 is a SENTRON 3-pole molded-case circuit breaker rated 25 A at 40 °C, with a TM210 thermal-magnetic release for system protection. Its interrupting capacity hits 65 kA at 240 V AC and 25 kA at 480 V AC — enough to handle high-fault panel feeders without cascading upstream.
Thermal derating — the real ampacity you get
At 40 °C ambient you get the full 25 A. Push to 45 °C and it drops to 24 A; at 70 °C it's 21 A. That's a 16 % reduction from the base rating — plan your panel thermal budget accordingly if the breaker sits near transformers or drives.
Footprint and panel fit
Dimensions are 76.2 mm wide, 129.4 mm tall, 75.1 mm deep — standard for a 3-pole SENTRON frame. The IP40 front protection means it's splash-safe on the operator face but not sealed for washdown; mount inside a rated enclosure for wet environments.