What this MCCB carries and where it fits
The Siemens 3VA1125-6EF32-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated 25 A at 40 °C, 3-pole, designed for line protection in distribution panels. Its breaking capacity hits 220 kA at 240 V and 154 kA at 415 V, so it handles high-fault utility feeds without cascading upstream. The built-in undervoltage release (UVR) drops the breaker if control voltage falls below the dropout threshold — common in emergency-stop or mains-monitoring circuits where a loss of control power must open the feeder.
Current derating and thermal limits
Full 25 A holds from 40 °C to 50 °C. At 55 °C it steps to 24 A, and at 70 °C it's 23 A. That's a shallow derating curve — you don't lose a full breaker size until well above typical panel ambient. The 800 V rated insulation voltage gives headroom on 690 V line-to-line systems. Maximum power loss is 11 W, which matters for heat buildup in a densely packed enclosure; account for it when sizing ventilation.
Physical fit and panel integration
Dimensions are 76.2 mm wide, 130 mm tall, 70 mm deep — standard 3-pole MCCB footprint for Siemens SENTRON 3VA frames. Mounts on DIN rail or direct panel. The undervoltage release adds a control-wire connection; verify wiring polarity per the terminal marking. No communication module or ground-fault monitoring on this variant.