The Siemens 3VA2125-8HK42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current with an ETU340 electronic trip unit. It carries a 440 kA interrupting capacity at 240 V AC and 330 kA at 415 V AC, making it suitable for high-fault-current industrial distribution panels where selectivity and arc-flash compliance drive the spec.
Breaking capacity and what it means for your panel
The 440 kA at 240 V and 330 kA at 415 V are the maximum fault currents this MCCB can safely interrupt without welding or rupturing. That rating governs SCCR (short-circuit current rating) for the downstream panel — if your transformer or utility feed can deliver fault current up to 440 kA at 240 V, this breaker clears it without cascading failure upstream. At 690 V the rating drops to 52.5 kA, still well above typical industrial service-entrance levels.
Thermal derating and continuous current
Rated 25 A continuous from 40 °C through 70 °C ambient — no derating curve to calculate across the typical panel temperature range. That flat profile simplifies BOM sizing: if the load draws 25 A or less, this breaker holds at any ambient up to 70 °C. The ETU340 electronic trip allows adjustable overload and short-circuit thresholds, so the same frame covers a range of downstream cable and load protection settings.
Physical fit and panel integration
Measures 140 mm wide by 181 mm tall by 86 mm deep — a 4-pole frame that fits standard MCCB panel cutouts. The 86 mm depth includes the arc chamber and rear terminals; verify clearance behind the mounting plate for lug access. IP40 on the front face means tools and fingers are protected but the interior is not sealed against dust ingress — install in a rated enclosure for washdown or outdoor locations.