The Siemens SENTRON 3VA2125-6KP36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 25 A continuous current, built around the ETU850 electronic trip unit. It's designed for line protection in distribution panels and motor control centers where you need adjustable overload and short-circuit protection with communication capability.
Breaking capacity and selectivity planning
This MCCB delivers 242 kA breaking capacity at 240 V, dropping to 187 kA at 415 V and 440 V, then 121 kA at 500 V, and 3.7 kA at 690 V. That 242 kA at 240 V is a high-interrupting rating — useful for large transformer secondaries or busway feeds where fault current is substantial. The steep drop at 690 V (3.7 kA) means it's not the right choice for 690 V distribution with high available fault current; that's where a higher-rated frame or a current-limiting fuse would be needed.
Physical fit and panel integration
Dimensions are 105 mm wide, 181 mm tall, 86 mm deep — a standard 3-pole MCCB footprint for this SENTRON frame size. The 86 mm depth includes the case body; account for wiring space behind the panel door. IP40 on the front face means it's protected against tools and small wires entering the front, but not against water ingress — keep it inside a dry enclosure.
Trip unit and protection characteristics
The ETU850 electronic trip unit supports adjustable overload and short-circuit settings. Rated insulation voltage is 800 V. Power loss is 0.6 W.