What this MCCB carries and where it fits
The Siemens SENTRON 3VA1225-6EF32-0HC0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current of 250 A up to 50 °C ambient before the thermal derating curve begins to step down — 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. That derating profile matters when you pack this into a warm enclosure; the 57 W maximum power loss at rated load is the heat you need to vent. Breaking capacity climbs with voltage: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. The rated insulation voltage is 800 V, so the internal clearances are sized for 690 V switching duty with headroom. For a panel designer, the 220 kA at 240 V figure tells you this breaker handles high-fault utility feeds without cascading upstream — useful for main or tie positions in large distribution boards.
Built-in accessories and what they mean for integration
This variant ships with a factory-installed shunt trip (STL) release and two HQ auxiliary switches. The shunt trip lets a remote signal — from a fire alarm relay, emergency-stop contactor, or PLC output — trip the breaker electrically without an operator reaching the handle. The two auxiliary switches give you position feedback (open/closed) for status monitoring or interlocking. No undervoltage release, no ground-fault module, no communication function on this order code; if you need those, you are looking at a different 3VA suffix. Dimensions are 105 mm wide by 158 mm tall by 70 mm deep — a standard 3-pole MCCB footprint for panel-mounting on a backplate or DIN rail adapter. The 70 mm depth keeps it clear of most gland plates and cable troughs.