The Siemens SENTRON 3VA1125-5EF32-0DC0 is a 3-pole molded case circuit breaker (MCCB) rated for 25 A continuous current, with a massive 187 kA interrupting capacity at 240 V — that's the kind of headroom you spec when the fault current on the secondary side of a big transformer is ugly, or when you need to coordinate downstream breakers without cascading failure.
What the ratings mean on the panel
This MCCB holds its full 25 A rating from 40 °C up to 50 °C ambient, then derates gently — 24 A at 55 °C, 23 A at 70 °C. That means in a sealed, hot panel near a motor drive or transformer, you don't lose much capacity. The 70 mm depth and 76.2 mm width fit a standard 3-pole MCCB footprint on the DIN rail or panel-mount plate; no need to re-lay out the gland plate if you're swapping into an existing SENTRON cutout. Breaking capacity drops as line voltage climbs: 121 kA at 415 V, 75.6 kA at 440 V, still 17 kA at 500 V and 690 V. For a 400 V industrial panel, 121 kA SCCR covers most transformer-fed busways. The 800 V rated insulation voltage (Ui) means the internal clearances are sized for 690 V line-to-line systems without derating the dielectric.
Built-in release and auxiliaries
This variant ships with an undervoltage release (UVR) integrated — when control voltage drops below the dropout threshold, the breaker trips. That's a common spec for emergency-stop circuits or safety-related disconnect chains where loss of control power must open the main breaker. It also carries two HQ auxiliary switches for remote status indication, so the PLC sees the breaker state without an add-on module. The product design is line protection (not motor or generator protection), meaning the thermal-magnetic trip curve is set for cable and busbar protection. If you're using it to protect a motor branch, the inrush may nuisance-trip unless you oversize or switch to a motor-protective breaker. Maximum power loss is 11 W — negligible for panel thermal budgeting but worth noting if the enclosure is densely packed.