Rated 250 A, breaking capacity across the voltage range
The Siemens SENTRON 3VA1225-4GF42-0KA0 is a 4-pole molded case circuit breaker (MCCB) rated at 250 A continuous, with a TM240 thermal-magnetic overcurrent release. It carries a shunt trip (STL) auxiliary release for remote tripping — useful in emergency-stop or undervoltage control schemes where you need to drop the breaker from a PLC or pushbutton. Breaking capacity steps are given per voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, 17 kA at 500 V, and 11.9 kA at 690 V. That covers most industrial distribution voltages up to 690 V, with the highest fault-interrupting ability at the lower voltages — typical for a line-protection MCCB sized for high-fault panels.
Temperature derating and thermal management
The breaker holds full 250 A rating up to 50 °C ambient. Above that it derates linearly: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. Maximum power loss is 57 W, so if you're packing several breakers in a closed panel, factor that heat into your ventilation or forced-air calculation.
Panel fit and mounting
Dimensions are 140 mm wide, 158 mm high, 70 mm deep — a standard 4-pole MCCB footprint that mounts on a DIN rail or directly to a backplate. Rated insulation voltage is 800 V, and the operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C.