What it is and what it does
The Siemens SENTRON 3VA2225-8KP42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 250 A continuous current, fitted with an ETU850 electronic trip unit. It's designed for line protection in distribution panels and switchgear, with a breaking capacity of 440 kA at 240 V and 330 kA at 415 V — numbers that tell you it can handle high-fault-current scenarios without cascading failure upstream.
Breaking capacity and thermal derating — the real-world limits
The interrupting ratings span the voltage range: 440 kA at 240 V, 330 kA at both 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. That 52.5 kA at 690 V is the one to watch if you're feeding a 690 V drive or transformer — it's still substantial but a fraction of the low-voltage number. Thermal derating is published stepwise: the breaker holds full 250 A up to 50 °C ambient, then drops to 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your panel hits 60 °C on a summer afternoon, you're down to 225 A — plan the load accordingly.
Panel fit and integration notes
Dimensions are 181 mm high, 140 mm wide, 86 mm deep — a standard MCCB footprint that drops into most SENTRON-compatible distribution blocks or panel-mount cutouts. The IP40 front protection means it's fine inside a closed enclosure but not for washdown areas. Rated insulation voltage is 800 V, so it's suited for 690 V systems with margin. Power loss is 48 W maximum — factor that into your enclosure thermal budget if you're stacking several breakers in a sealed cabinet.