25 A MCCB for line protection — what the ratings mean
The Siemens SENTRON 3VA2025-8KQ32-0AA0 is a 3-pole molded case circuit breaker rated for 25 A continuous current, designed specifically for line protection duty. The 25 A full-scale value means it protects downstream conductors and loads up to that current under normal conditions — not a motor-protection curve, but a feeder or distribution circuit. Breaking capacity runs from 440 kA at 240 V down to 52.5 kA at 690 V (–), which covers most industrial service-entrance and sub-distribution applications; the 330 kA at 415 V is the figure most panel builders will reference for European 400 V networks. Insulation voltage rated at 800 V gives headroom for 690 V systems without derating the dielectric. The unit includes a communication function and ground-fault monitoring via summation current formation on the L-conductor — so it can report status and leakage to a higher-level system without an add-on module. Power loss is a low 0.5 W, negligible in a dense panel. Operating temperature spans -25 °C to 70 °C, with storage from -40 °C to 80 °C; the 70 °C operating ceiling matches the derating curve for the 25 A rating held flat across the full ambient range (–).
Panel fit and mounting
At 105 mm wide, 181 mm tall, and 86 mm deep, this MCCB occupies a standard 3-pole molded-case footprint. It mounts directly onto a DIN rail or panel plate via the SENTRON quick-latch system — no tools needed for snap-on, though a screwdriver is required for terminal torque. The 86 mm depth is shallow enough to clear most 200 mm deep enclosures with room for wiring gutters. For a panel OEM wireman: the 25 A rating at 40 °C means no derating in a 40 °C ambient; if your enclosure internal temp hits 70 °C, the same 25 A holds — the breaker is thermally stable across the full range.