What it is and what the ratings mean
The Siemens SENTRON 3VA2125-5JP36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current of 25 A across its full ambient temperature range from 40 °C up to 70 °C — no derating needed in a warm panel, which simplifies panel design when the breaker sits near other heat sources. Its interrupting ratings are the headline: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That 187 kA at 240 V means it can safely clear a fault on a low-voltage distribution board with very high available fault current — common in industrial switchgear downstream of a large transformer — without the arc flashing over or the breaker rupturing. The ETU550 electronic trip unit provides adjustable overload and short-circuit protection curves, plus communication capability for remote monitoring and trip indication via a bus system — useful for a plant engineer tracking breaker status from a control room rather than walking the panel line.
Where it fits in the panel
The 3VA2125-5JP36-0AA0 mounts on a DIN rail or directly into a panel via screw terminals. Its dimensions — 105 mm wide, 181 mm tall, 86 mm deep — mean it occupies a standard 3-pole MCCB footprint, so it drops into an existing SENTRON or 3VA-series panel layout without re-drilling the backplate. Front-face protection is IP40, sufficient for a clean indoor panel environment; the breaker is not rated for washdown or outdoor exposure.
Lifecycle and sourcing reality
For a BOM line that calls out this exact order code, the 25 A rating at 70 °C and the 187 kA SCCR at 240 V confirm fit for a feeder or branch circuit in a high-fault panel. Availability and current pricing are confirmed at quote time against an RFQ.