The Siemens SENTRON 3VA1225-5EF42-0DC0 is a 4-pole molded case circuit breaker (MCCB) rated for line protection, carrying 250 A continuously at 40 °C ambient. Its interrupting capacity reaches 187 kA at 240 V — enough to clear high-fault conditions in distribution panels without cascading upstream breakers. Rated insulation voltage is 800 V, and the breaker ships with an undervoltage release (UVR) plus two HQ auxiliary switches for status feedback to a PLC or annunciator panel.
Current derating and thermal management
Full 250 A rating holds from 40 °C through 50 °C; above that it derates linearly to 223 A at 70 °C. If the panel ambient runs above 50 °C, size the feeder and buswork for the derated value, not the nameplate. Maximum power loss is 59.5 W — account for that heat in the enclosure sizing, especially in a sealed cabinet with multiple breakers side by side.
Breaking capacity by voltage
Interrupting rating drops as system voltage rises: 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. Verify the available fault current at the point of installation — the 690 V figure is the floor for this frame.