The Siemens 3VA2125-8KQ32-0AA0 is a SENTRON molded case circuit breaker (MCCB) built for line protection in industrial power distribution. It's a 3-pole unit rated at 25 A continuous current, and that rating holds flat from 40 °C all the way up to 70 °C — no derating curve to chase in a warm panel. The ETU860 electronic trip unit handles the overcurrent release, so you get adjustable protection curves, not a fixed thermal-magnetic snap.
Breaking capacity — the number that decides the bus
The headline here is the interrupting rating: 440 kA at 240 V, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. That's a high-energy breaker — it's meant for main or feeder positions where fault current can pile up from multiple transformers or motor contributions. The 440 kA figure at 240 V tells you it can clear a bolted fault on a large low-voltage secondary without the arc re-striking. For a panel builder, that means this breaker sits at the head of a distribution board, not in a branch circuit.
What the ETU860 release gives you
The ETU860 is an electronic trip unit, so you're looking at adjustable long-time pickup, short-time pickup, and instantaneous settings — plus ground-fault monitoring via summation current formation on the L-conductor. That ground-fault function is built into the release, not an add-on module. It communicates (communication function is present), and there's an optional motor drive available for remote charging. The power loss is a minimal 0.5 W at rated current, which keeps the interior of the MCCB cool over its service life.
Physical fit and environment
Dimensions: 105 mm wide, 181 mm tall, 86 mm deep. That's a standard MCCB footprint for a 3-pole frame in this class — it'll drop into a SENTRON distribution board or a panel with a DIN-rail adapter. Front face carries IP40 protection, so it's fine in a clean electrical room but not for washdown areas. Operating temperature range from -25 °C to 70 °C; storage from -40 °C to 80 °C. The IP40 on the front means the breaker face is protected against tools and wires larger than 1 mm, but the terminals themselves will need a separate finger-safe shroud if the panel requires it.
Lifecycle and sourcing
This part is listed as current production — no end-of-life notice on record. It's an active catalog item in the SENTRON 3VA2 family. For a BOM line, that means you can specify it without worrying about a last-time-buy window. Sourced and quoted to order against an RFQ through independent distribution; availability and current pricing confirmed at quote time.