What this 250 A MCCB delivers in the panel
The Siemens SENTRON 3VA1225-4EF32-0KA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It's built for line protection — meaning it sits at the feeder or main distribution point, not downstream on motor or branch circuits. The breaking capacity is 121 kA at 240 V and 75.6 kA at 415 V, so it handles high-fault utility connections without cascading upstream. The front face carries IP40 protection — fine for a dry enclosure, but keep it behind a sealed gland plate if washdown is nearby.
Current derating and thermal reality
This breaker holds its full 250 A rating up to 50 °C ambient. Above that, it derates: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. If the panel runs hot — say, next to a drive cabinet or in a non-climate-controlled electrical room — size the upstream conductor for the derated value, not the nameplate 250 A. The TM240 release is fixed; there's no electronic adjustment or communication module on this variant.
Mounting and integration notes
Dimensions: 105 mm wide, 158 mm high, 70 mm deep. It's a panel-mount MCCB — no DIN-rail clip, so budget for a mounting plate and screw-down lugs. The shunt trip (STL) auxiliary release is included (order code 3VA9688-0BL33 for the integrated trip unit if you need a spare). No auxiliary contacts, undervoltage release, or ground-fault monitoring on this build. If you need those, you're looking at a different version of the 3VA platform.