The Siemens 3VA1225-5EF42-0JH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in industrial power distribution. It carries a 250 A continuous rating at 40 °C and breaks up to 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 — that 187 kA figure at 240 V means it handles high-fault utility feeds or transformer secondaries without cascading upstream.
Current derating and thermal management
Rated 250 A from 40 °C through 50 °C, then derates to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. That 223 A at 70 °C is the figure to use if the breaker lives in a hot enclosure — the 250 A nameplate applies only up to 50 °C ambient. Maximum power loss is 57 W, so factor that into panel heat calculations.
Construction and auxiliary options
Four-pole construction with a rated insulation voltage of 800 V. Comes with a shunt trip release (STL) for remote tripping, plus two auxiliary switches and one trip alarm switch (HQ) — that HQ contact signals a fault condition separately from the aux position, handy for PLC-based fault annunciation. No undervoltage release, no ground-fault monitoring, no communication module on this variant.