What this MCCB delivers
The Siemens SENTRON 3VA2225-5JQ32-0KH0 is a 3-pole molded case circuit breaker rated 250 A at 40 °C, with an adjustable trip range from 50 A to 250 A full-scale. That adjustable band means you can fine-tune the overload protection to match the actual load without swapping the breaker — useful when a motor or transformer draw is slightly below the frame rating. Breaking capacity hits 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 500 V — numbers that put it in the high-fault category for industrial distribution. At 690 V it drops to 4.5 kA, so if your line runs at that voltage, you need to verify the available fault current stays under that limit. The 187 kA at 240 V is the headline figure for US-style 277/480 V panelboards where the high-side fault can be brutal. This is a line-protection design (not motor-protection), so the trip curve is shaped for cable and busbar protection. It carries a shunt trip release (STL) and two auxiliary switches plus one trip alarm switch (HQ) — enough for remote status and emergency trip via a pushbutton or PLC output.
Thermal derating and panel fit
The breaker holds 250 A continuously up to 50 °C ambient. Above that it derates: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your enclosure runs hot — say a packed panel near a furnace line — you need to account for that drop. Max power loss is 48 W, which adds to the enclosure heat load. Dimensions are 181 mm high, 105 mm wide, 86 mm deep — a standard SENTRON 3VA frame size that fits existing 3VA panel cutouts. The 105 mm width means it occupies three 35 mm DIN spaces (assuming DIN-rail mounting). Storage range is -40 °C to 80 °C; operating range is -25 °C to 70 °C.