Siemens SENTRON 3VA2225-8KP32-0AA0 — 250 A MCCB with ETU850 Trip Unit
The Siemens SENTRON 3VA2225-8KP32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current at 40 °C, using the ETU850 electronic trip unit for adjustable protection curves. It is configured as a line protection device, meaning it is intended for feeder or main breaker duty in distribution panels, not for direct motor starting. Breaking capacity is 440 kA at 240 V, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V — figures that place it in the high-interrupting category for industrial switchgear where fault currents can be severe. The 800 V rated insulation voltage (Ui) confirms it is designed for 690 V systems with margin. Physical footprint: 181 mm height, 105 mm width, 86 mm depth. The IP40 front protection means the breaker face is protected against solid objects over 1 mm but not against water ingress — standard for indoor panel mounting where the enclosure provides the overall IP rating.
Thermal Derating and Operating Range
The 250 A rating holds from 40 °C through 50 °C ambient. Above that, derating applies: 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your panel ambient runs hot, size the breaker for the actual temperature, not the nameplate 250 A. Operating ambient range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. Maximum power loss at rated current is 48 W — relevant for thermal coordination inside a sealed enclosure. The ETU850 electronic trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection (though this variant ships without ground-fault monitoring). Communication function and other measurement functions are present, enabling integration with energy management systems.