What this MCCB carries and what it means for your panel
The Siemens SENTRON 3VA2225-5JQ32-0DA0 is a 3-pole molded case circuit breaker rated for line protection, with a full-scale current of 250 A and a minimum setting of 375 A — meaning it's sized for main feeder or large-load protection in distribution panels, not branch circuits. Its breaking capacity of 187 kA at 240 V and 121 kA at 415 V tells you it can safely clear high-fault-current events without cascading upstream, which is the deciding spec for a panel with a high-available-fault utility transformer. The unit ships with an undervoltage release (UVR) fitted, so if you're specifying for a safety circuit that needs to drop the breaker on loss of control voltage, that's already in the package.
Thermal derating — the real ampacity for your enclosure
At 40 °C this MCCB carries its full 250 A rating, and it holds that rating through 50 °C — no derating needed in a typical ventilated panel. At 55 °C it drops to 238 A, at 60 °C to 225 A, at 65 °C to 213 A, and at 70 °C to 200 A. If your panel ambient runs above 50 °C, size the breaker for the derated value, not the nameplate 250 A. The maximum operating ambient is 70 °C; storage range is -40 °C to 80 °C.
Breaking capacity across voltages — verify your fault level
The 3VA2225-5JQ32-0DA0 delivers 187 kA at 240 V, 121 kA at both 415 V and 440 V, 75.6 kA at 500 V, and 4.5 kA at 690 V. For a 480 V panel (common in North America), the relevant figure is the 500 V rating at 75.6 kA — that is the SCCR you compare against the available fault current at the breaker's location. The sharp drop at 690 V (4.5 kA) tells you this is not a 690 V main breaker; it is a 500 V-class device.
Physical fit and panel integration
The breaker measures 105 mm wide, 181 mm high, and 86 mm deep. That 105 mm width (4.13 in) is a standard 3-pole MCCB footprint for this class — it fits Siemens SENTRON mounting plates and common DIN-rail adapters without extra panel rework. The 86 mm depth (3.39 in) means it clears most 200 mm-deep enclosures with room for wiring gutters. Power loss is 50.5 W maximum; account for that heat in your enclosure thermal calculation, especially if the panel is sealed or has multiple breakers ganged.