Motor protection MCCB for high-current branch circuits
The Siemens 3VA2450-5MN32-0KH0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for motor protection — meaning its trip curve is shaped to handle the inrush and thermal profile of induction motors while still clearing a bolted fault. Rated 500 A continuously at 40 °C (derates to 480 A at 70 °C), it sits on the high end of the 3VA2 frame, sized for large motor branch circuits or feeder duty in a panel. The 3-pole body carries a shunt trip (STL) auxiliary release and two auxiliary switches plus one trip alarm switch, so it can signal a PLC or safety relay on fault. Interrupting capacity is the headline here: 187 kA at 240 V AC, 121 kA at 415/440 V, 75.6 kA at 500 V, and 9 kA at 690 V. That 187 kA figure at 240 V means this breaker can sit upstream of a large transformer or a high-fault panelboard without needing a current-limiting fuse ahead of it — it clears the fault itself. At 690 V the 9 kA rating is lower, but that voltage is uncommon in industrial distribution; the 415 V / 121 kA is the practical number for most 400 V-class systems.
Dimensions and panel fit
The breaker measures 248 mm high by 138 mm wide by 110 mm deep. That 110 mm depth is the body only — add for the rotary handle or extended terminals if used. The 138 mm width (5.43 in) is a standard 3-pole MCCB footprint for this frame class; it fits Siemens SENTRON mounting plates and busbar adapters without adaptor plates. Phase failure detection is built in, so no external phase-loss relay is needed for motor protection.
Thermal and environmental limits
Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 500 A rating holds flat from 40 °C to 50 °C, then drops 5 A per 5 °C step to 480 A at 70 °C — useful to know if the breaker is in a hot enclosure near a motor or drive. Maximum power loss at rated current is 99 W, so ventilation in the panel matters for thermal coordination.