What it is and what it does in the panel
The Siemens SENTRON 3VA2125-8KP46-0AA0 is a 4-pole molded case circuit breaker (MCCB) designed for line protection in low-voltage distribution. It carries a continuous current rating of 25 A and is adjustable from a minimum of 38 A up to a maximum of 300 A, giving the specifying engineer a wide band to fine-tune overload protection to the actual load without swapping the breaker frame. The breaker uses an ETU850 electronic trip unit, which enables communication functions — a key feature for panel builders integrating into a networked power-monitoring scheme where trip events, load profiles, and status need to report back to a BMS or SCADA layer.
Breaking capacity and what it means for coordination
Rated breaking capacity is 440 kA at 240 V AC, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. These numbers mean the breaker can safely interrupt a fault at those voltage levels without cascading upstream — critical for selective coordination studies where the main breaker must clear a downstream short without tripping the feeder. The insulation voltage is rated 800 V, so the breaker is suited for 690 V line-to-line systems common in industrial plants in North America and Europe.
Physical fit and environmental limits
Dimensions: 86 mm deep, 140 mm wide, 181 mm high — a standard panel-mount footprint for this frame size. Front protection rating is IP40, so it is suitable for dry indoor enclosures where tools or accidental contact are the concern, not washdown. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Continuous current rating holds steady at 25 A across the entire operating range from 40 °C up to 70 °C — no derating needed within that window.