What this MCCB delivers for a 250 A feeder
The Siemens SENTRON 3VA2225-5HL42-0HH0 is a 4-pole molded case circuit breaker rated for 250 A continuous current at 40 °C, with a breaking capacity of 187 kA at 240 V AC and 121 kA at 415 V AC. Those numbers mean it can clear a bolted fault on a 250 A feeder without the arc flashing over to adjacent gear — the interrupting rating is high enough for most secondary-side distribution in industrial plants. The 4-pole design covers three-phase plus neutral protection, which is standard for TN-S or TN-C-S systems where you need to break the neutral on a fault. It carries a shunt trip release (STL) and two auxiliary switches plus one trip alarm switch (HQ), so it can signal its status back to a PLC or annunciator panel. No undervoltage release is fitted — if the application requires UVR, that needs to be added externally. The line protection design (not motor protection) means the thermal-magnetic curve is tuned for cable and busbar protection, not for motor overload curves.
Sizing and derating for panel builders
Footprint is 140 mm wide by 181 mm tall by 86 mm deep — a standard SENTRON 3VA2 frame size. It mounts on a DIN rail or directly to a backplate via the four corner slots. At full 250 A load the maximum power loss is 48 W, so the enclosure needs enough ventilation or forced cooling to keep internal ambient below 40 °C if you want to hold the full rating. Above 50 °C the breaker must be derated: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, 213 A at 70 °C. That derating curve is published and repeatable — factor it into your panel thermal budget.