What it is and what it does
The Siemens 3VA2125-7KP46-0AA0 is a SENTRON molded case circuit breaker (MCCB) with 4 poles, rated for a continuous current of 25 A across the full ambient range from 40 °C up to 70 °C — no derating needed in a warm panel. It carries an ETU850 electronic trip unit, which gives you adjustable time-current curves (tr min 0.5 s, tr max 25 s) and configurable N-conductor protection (OFF, 40 % to 160 %). The interrupting ratings are substantial: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.8 kA at 690 V. That kind of SCCR headroom means it can sit upstream of smaller branch breakers without worrying about cascading failure — useful for a main or feeder in a high-fault industrial panel.
Dimensions and panel fit
The breaker measures 140 mm wide, 181 mm high, and 86 mm deep. That 86 mm depth is the body depth — it fits standard MCCB mounting footprints in a distribution panel. The front face carries an IP40 protection class, so it is protected against tools and small solid objects but not sealed against moisture; keep it inside a rated enclosure.
Communication and monitoring
The ETU850 release includes a communication function and an other measurement function — meaning it can report trip data and power quality metrics over a bus, though the specific protocol is not listed here. For a controls integrator, that means you can pull event logs and load profiles without climbing to the panel. The latching endurance is rated at 20 000 operations, which is typical for a solid electronic-trip MCCB in a feeder role.