Siemens 3VA2125-5JP42-0AA0 — 25 A SENTRON MCCB with ETU550 Trip
The Siemens SENTRON 3VA2125-5JP42-0AA0 is a 4-pole molded case circuit breaker rated for 25 A continuous current, built around the ETU550 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. The ETU550 trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves — that's the kind of selectivity coordination a site electrical engineer needs to stage breakers downstream without nuisance trips on a fault. At 240 V it interrupts 187 kA; at 415 V it holds 121 kA; at 690 V the rating drops to 3.7 kA. That 187 kA figure at 240 V is the headline — it handles high available fault current at the service entrance without cascading upstream. Panel footprint is 140 mm wide by 181 mm high by 86 mm deep — that's a 5.51 by 7.13 by 3.39 inch envelope. It mounts on a DIN rail or direct-panel, so the wireman needs to check gland-plate clearance and side-to-side spacing for heat dissipation at full load. The IP40 front protection means it's sealed against tools and solid objects larger than 1 mm on the face — fine for a dry indoor panel, but not for washdown environments. Operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C.
Integration — DIN Rail, Communication, and Derating
The 3VA2125-5JP42-0AA0 snaps onto a 35 mm DIN rail per EN 60715. The 140 mm width occupies four 27 mm module spaces — plan your enclosure fill factor accordingly. Side-to-side clearance for heat dissipation follows the standard SENTRON derating rules; at 25 A continuous and 0.6 W max power loss, thermal management is straightforward in a ventilated panel. The communication function means it can integrate with a fieldbus system via the SENTRON communication module — useful for a controls integrator who wants remote trip indication, load monitoring, and energy data without running separate wires back to the PLC. No undervoltage release, no voltage trigger, no ground-fault monitoring version on this variant. If your application requires undervoltage protection or GFCI, you need the accessory modules (5SQ2670-2YA06 for shunt trip, 5SQ2670-2YA63 for UVR).