Siemens 3VA2125-0KP36-0AA0 — 25 A SENTRON MCCB with ETU850 Trip
The Siemens 3VA2125-0KP36-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current, built around the ETU850 electronic trip unit. It's a 3-pole line-protection device with a 440 kA interrupting capacity at 415 V AC — that rating tells you it can clear a fault up to that level without upstream devices needing to coordinate, which matters when you're protecting a feeder in a high-fault panel. The ETU850 gives you adjustable N-conductor protection (OFF, 40% to 160%) and a communication function, so it fits into a monitored distribution scheme.
The ETU850 trip unit provides electronic overload and short-circuit protection with adjustable settings, which gives you finer coordination than a fixed thermal-magnetic breaker. The 440 kA at 415 V and 187 kA at 690 V are the maximum fault currents the breaker can safely interrupt at those voltages — in a panel with available fault current below those numbers, this breaker clears the fault without catastrophic failure.
Physical Integration — Panel Fit
The 3VA2125-0KP36-0AA0 measures 105 mm wide, 181 mm high, and 86 mm deep. That width is the critical dimension for DIN-rail or panel-mount spacing — three of these side by side take 315 mm of rail width.