The Siemens SENTRON 3VA1225-6EF32-0JA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current (Iu) in a line protection configuration. It carries a TM240 thermal-magnetic overcurrent release and a shunt trip (STL) auxiliary release for remote tripping. The interrupting ratings span 220 kA at 240 V down to 17 kA at 690 V, which gives selectivity headroom for high-fault panels upstream of smaller branch breakers.
Interrupting capacity and thermal derating
At 240 V the breaker clears 220 kA — that is the full short-circuit current available at a large transformer secondary. At 415 V it still holds 154 kA, and at 440 V it drops to 36 kA; at 690 V the rating is 17 kA. These are the values that govern coordination with upstream switchgear; if your panel's prospective fault current at the breaker terminals exceeds the applicable voltage-column rating, you need a current-limiting fuse ahead or a larger frame. Thermal derating is flat at 250 A from 40 °C through 50 °C, then steps down to 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C. The rated insulation voltage is 800 V, and the front face carries IP40 protection — suitable for enclosed panel mounting where no water ingress reaches the breaker face.
Release and accessory configuration
The TM240 release is a fixed thermal-magnetic trip unit set for 250 A frame; there is no phase-failure detection, no ground-fault monitoring, and no communication module on this variant. The shunt trip (STL) is factory-fitted — order code 3VA9688-0BL32 for the integrated auxiliary trip if you need a spare. Latching endurance is rated at 15 000 operations. No auxiliary contact version is included; if you need status feedback to a PLC, you add a separate auxiliary switch block.
Physical fit and panel integration
Dimensions are 105 mm wide, 158 mm high, and 70 mm deep. The breaker mounts on a DIN rail or directly to a backplate via the SENTRON 3VA mounting accessories. The 70 mm depth is the body depth excluding the handle throw — verify clearance in a shallow gland-plate enclosure. The width of 105 mm matches the standard 3VA frame footprint; if your existing panel was built around a 3VA1010 frame (100 A class), the mounting hole pattern and bus-bar centres are identical, so this 250 A unit drops in without rewiring the bus.