The Siemens 3VA1125-6GD46-0AA0 is a SENTRON-series molded case circuit breaker (MCCB) for line protection — the main disconnect and fault interrupter in a distribution panel, motor control center, or feeder circuit. It is a 4-pole device rated 25 A continuous, meaning it protects a 25 A branch circuit and will not nuisance-trip at that load under normal conditions. The breaking capacity is where this part earns its place: 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at both 500 V and 690 V.
Panel fit and thermal derating
Dimensions: 130 mm tall, 101.6 mm wide, 70 mm deep. The 4-pole width (101.6 mm) is roughly 4 inches, standard for a 4-pole MCCB frame; verify the DIN-rail or mounting-plate pattern matches your existing backpanel layout. Thermal derating is minimal for this frame: it carries the full 25 A from 40 °C through 50 °C ambient, then drops only to 24 A at 55 °C and 60 °C, and 23 A at 65 °C and 70 °C. In a hot panel — near a transformer or in a non-climate-controlled enclosure — you lose only 1–2 A before the trip curve shifts. Maximum power loss is 8.5 W, so the breaker itself does not add significant heat to the enclosure. Front protection is IP40 — finger-safe from the front but not sealed against dust ingress.