Line protection with ETU850 — what the ratings mean for your panel
The Siemens SENTRON 3VA2225-6KP32-0HH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a rated continuous current Iu of 250 A and a rated insulation voltage Ui of 800 V. The ETU850 electronic trip unit gives you adjustable overload and short-circuit protection curves, plus a communication function for remote monitoring — useful when you need to integrate breaker status into a BMS or PLC without separate aux contacts. Breaking capacity is the headline number here: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 6 kA at 690 V. At 415 V, 187 kA means this breaker can safely interrupt a fault current up to that level without welding contacts or cascading upstream — critical for high-fault installations like transformer secondaries or large motor control centers. The 6 kA at 690 V is the limit for 690 V line-to-line systems; verify your available fault current at that voltage before specifying. Thermal derating is published per ambient: full 250 A up to 50 °C, then 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 above 50 °C, size the breaker for the derated value — the 200 A at 70 °C floor still gives headroom for many 200 A loads. Maximum power loss is 48 W, which matters for enclosure heat rise calculations in sealed cabinets.
Auxiliary contacts and integrated trip — what ships inside
This variant ships with 2 auxiliary switches plus 1 trip alarm switch (HQ type), giving you three separate signal paths for status feedback. The auxiliary release is a shunt trip (STL) — a voltage-triggered release that lets a remote signal (e-stop, PLC output, fire alarm) open the breaker. There is no undervoltage release and no ground fault monitoring module on this build. The integrated auxiliary trip is order code 3VA9688-0BL30; the basic switch assembly is 3VA2225-6KP32-0AA0. If your BOM requires undervoltage or ground fault, this is not the variant.
Panel fit — dimensions and mounting
Dimensions: 105 mm wide, 181 mm high, 86 mm deep. The 105 mm width is the standard 3-pole MCCB footprint for this frame size — it occupies three 35 mm DIN spaces (or the equivalent bolted bus mount). The 86 mm depth includes the arc chamber and terminals; verify clearance to the enclosure door or gland plate, especially if you are retrofitting into a panel originally built for a smaller frame. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.