What the ratings mean for fit
The Siemens SENTRON 3VA1225-5EF32-0JA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current at 40 °C, with no derating needed up to 50 °C — it holds full 250 A through that range. Above 55 °C it steps down: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. That means in a warm panel or next to other heat sources, you still get 223 A at the 70 °C upper operating limit. The interrupting ratings climb fast at lower voltages: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. For a 480 V panel, you're looking at roughly 75 kA SCCR — plenty of headroom for most industrial services. Insulation voltage is rated 800 V, so it's comfortable on 690 V systems. This is a line-protection design (not motor-protection), so it's sized for feeder or main breaker duty. The built-in shunt trip (STL) lets you remotely trip the breaker via a control signal — useful for emergency-stop circuits or interlocking with a fire-alarm panel. No undervoltage release, no ground-fault monitoring, no communication module on this variant. It's a straight 3-pole thermal-magnetic with a shunt trip added. Power loss maxes at 57 W, which matters for enclosure heat budgeting.
Panel fit and mounting
Dimensions: 70 mm deep, 105 mm wide, 158 mm tall. That's a standard SENTRON 3VA form factor — mounts on a DIN rail or directly to a backplate via the screw terminals. The 105 mm width is the same as other 250 A frames in the family, so if you're swapping from a 3VA1112-5EE32-0AA0 or similar, the footprint is identical. No trip indicator on the front face, so you'll need a panel-mounted indicator or rely on the shunt trip status.