What this MCCB carries and what it means for your panel
The Siemens 3VA1225-4EF32-0CA0 is a SENTRON molded case circuit breaker (MCCB) rated 250 A at 40 °C, with a 3-pole configuration and a TM240 thermal-magnetic release. This is a line-protection device, meaning it sits at the main or feeder breaker position in a distribution panel, sized for continuous loads up to 250 A before the thermal trip curve begins to act. The 250 A rating holds flat from 40 °C through 50 °C, then derates to 243 A at 55 °C and 223 A at 70 °C — useful to know if the breaker lives in a hot enclosure or near other heat sources. The interrupting ratings span the common industrial voltages: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, 17 kA at 500 V, and 11.9 kA at 690 V. For a 480 V panel (common in North America) the 52.5 kA at 440 V figure is the closest reference — that SCCR headroom covers most transformer-fed service entrances without needing a current-limiting fuse upstream. The 690 V rating at 11.9 kA confirms it can handle 600 V class systems, though with reduced fault capacity. This variant includes an undervoltage release (UVR) — the auxiliary release trips the breaker when supply voltage drops below a set threshold. That makes it a fit for applications where you need automatic disconnection on brownout or loss of control power: think safety circuits, emergency-stop chains, or motor control centers where a downstream starter must drop out if the MCCB opens. The UVR is factory-fitted; no field kit to add.
Physical fit and integration
Dimensions: 105 mm wide, 158 mm tall, 70 mm deep. The 105 mm width is the standard 3-pole MCCB footprint for this SENTRON frame size — it occupies three 35 mm DIN-rail modules. Depth of 70 mm leaves clearance for rear-mounted busbars or cable lugs in a typical distribution enclosure. Panel builders should verify the busbar connection kit and lug size separately; the breaker ships without lugs.
Thermal management and power loss
Maximum power loss is 59.5 W at rated current. That heat must be dissipated into the enclosure; for a sealed panel, factor this into the thermal budget alongside other breakers and contactors. The operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C.