What it is and what it does
The Siemens 3VA1025-4ED36-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — meaning it sits upstream of a load to guard against overloads and short circuits, not to switch a motor directly. Rated 25 A at 40 °C with a TM210 thermal-magnetic overcurrent release, it clears faults up to 121 kA at 240 V AC and 75.6 kA at 415 V. The 3-pole construction suits three-phase distribution panels; the IP40 front protection keeps dust out of the enclosure face.
Breaking capacity — what the numbers mean for your panel
The interrupting ratings drop as voltage rises: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 11.9 kA at 690 V is the limiting figure for a 480 V or 600 V class panel — if your available fault current exceeds that, this breaker won't hold. The 121 kA at 240 V is typical for a main breaker in a low-voltage distribution board where the transformer is close.
Thermal derating and panel integration
Rated current holds flat at 25 A from 40 °C to 50 °C (–), then steps down to 24 A at 55 °C and 60 °C, and 23 A at 65 °C and 70 °C. In a sealed enclosure with no forced airflow, expect to derate to 23 A if ambient hits 65 °C. The 70 mm depth and 76.2 mm width fit a standard 3-pole MCCB footprint on DIN rail or panel-mount — measure your existing cutout against those numbers before ordering. Maximum power loss is 8.5 W, negligible for thermal budgeting in a populated cabinet.