MCCB with ETU850 for line protection
The Siemens SENTRON 3VA2225-6KP32-0AA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, carrying a continuous rated current of 250 A and an insulation voltage of 800 V. The ETU850 electronic trip unit gives you adjustable overload and short-circuit protection curves, plus a communication function for integration into a monitored distribution system — useful when you need to track breaker status or trip events from a central controller.
Breaking capacity across the voltage range
This MCCB delivers 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 4.5 kA at 690 V. The steep drop at 690 V means you need to verify the available fault current at that voltage level — the 4.5 kA rating is adequate for most 690 V distribution but not for high-fault locations. At 415 V and below, the 187–242 kA range provides substantial headroom for high-capacity transformer secondaries or parallel-fed switchgear.
Thermal derating and ambient temperature
The breaker holds its full 250 A rating up to 50 °C ambient. Above that, it derates linearly: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If the panel ambient runs hot — say, a sealed enclosure near a furnace line — you need to account for this curve when sizing the breaker for the load. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C.
Panel fit and dimensions
The breaker measures 105 mm wide, 181 mm high, and 86 mm deep. It mounts on a DIN rail or directly to a backplate via the standard 3-pole MCCB footprint. The IP40 front protection is suitable for enclosed distribution panels.