MCCB with line protection focus
The Siemens SENTRON 3VA1225-5EF42-0KC0 is a 4-pole molded case circuit breaker rated 250 A at 40 °C, designed for line protection in distribution panels. Its interrupting capacity reaches 187 kA at 240 V and 121 kA at 415 V, meaning it can safely clear high-fault currents without upstream coordination failure — critical for main breaker or large feeder applications where available fault current is high.
The breaker holds 250 A continuously up to 50 °C ambient; above that it derates to 243 A at 55 °C and 223 A at 70 °C. Maximum power loss is 57 W — a factor for enclosure heat rise calculations when multiple breakers are ganged in a panel.