What this MCCB carries — and what it means for your panel
The Siemens 3VA2225-5HN42-0KC0 is a SENTRON molded case circuit breaker rated for 250 A continuous current (Iu) in a 4-pole configuration, built for line protection duty. The ETU350 electronic trip unit gives you adjustable overload and short-circuit protection curves — not a fixed thermal-magnetic, so you can dial in coordination with downstream breakers. Breaking capacity hits 187 kA at 240 V and still holds 121 kA at 415 V, which means it handles high-fault scenarios common in industrial main feeders or large distribution panels without needing a current-limiting upstream device. Rated insulation voltage is 800 V, so it's comfortable on 480 V and 600 V class systems with margin. The shunt trip (STL) auxiliary release lets you remotely trip the breaker via a control signal — useful for emergency-stop circuits or interlocking with a fire-alarm panel. Two HQ auxiliary switches are built in for status feedback to a PLC or annunciator.
Thermal derating and power loss — the real-world numbers
The breaker carries its full 250 A from 40 °C through 50 °C ambient. At 55 °C it derates to 241 A, at 60 °C to 232 A, at 65 °C to 222 A, and at 70 °C to 213 A. If your panel runs hot — say a packed enclosure near a furnace line — plan for that 213 A floor at the top end. Maximum power loss is 48 W, which matters for enclosure heat-rise calculations when you're stacking multiple breakers in a single section. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing, not running conditions.
Panel fit — dimensions and integration
Dimensions are 181 mm height, 140 mm width, 86 mm depth. That 86 mm depth is the body only — add clearance for the shunt-trip wiring and auxiliary cable exit on the left side. The 140 mm width is the standard 4-pole MCCB footprint for this class; verify the mounting base hole pattern matches your existing backplate if you're swapping in a live panel.