MCCB with ETU850 — what the ratings mean for your panel
The Siemens SENTRON 3VA2225-7KP32-0JH0 is a 3-pole molded case circuit breaker rated 250 A continuous current (Iu) with an ETU850 electronic overcurrent release. The 330 kA breaking capacity at 240 V (242 kA at 415 V, 187 kA at 500 V, 6.3 kA at 690 V) means it can safely interrupt fault currents up to those levels without upstream cascading — critical for high-fault installations like transformer secondaries or large motor control centers. The rated insulation voltage of 800 V gives headroom for 690 V systems. Thermal derating is explicit: the breaker carries 250 A up to 50 °C ambient, then steps down to 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your panel internal ambient runs above 50 °C, size the load accordingly — the 250 A rating is only valid within that envelope. The shunt trip (STL) design allows remote tripping via a control signal — useful for emergency-stop circuits or automated load shedding. The auxiliary contact configuration (2 auxiliary switches + 1 trip alarm switch HQ) provides status feedback for PLC or SCADA monitoring. Communication function is onboard, supporting integration into higher-level energy management systems.
Panel fit and integration
Dimensions: 86 mm depth, 105 mm width, 181 mm height — fits standard MCCB mounting footprints in distribution boards and motor control centers. The 3-pole design with line protection version is sized for feeder or main breaker duty in 250 A circuits. Maximum power loss of 48 W at rated current — account for this in enclosure thermal calculations, especially in sealed or high-density panels.