The Siemens SENTRON 3VA1150-4EF32-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated 50 A at 40 °C, designed for line protection in industrial distribution panels. Its breaking capacity reaches 121 kA at 240 V and 75.6 kA at 415 V, with a rated insulation voltage of 800 V.
Ratings and what they mean for fit
The 50 A rating is maintained from 40 °C up to 50 °C, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. This thermal derating curve matters when the breaker is mounted in a warm enclosure or alongside other heat-generating devices — the actual continuous current it can carry drops as ambient rises. The 121 kA breaking capacity at 240 V and 75.6 kA at 415 V mean this MCCB can safely interrupt high fault currents typical of large transformer-fed panels or motor control centers. At 500 V and 690 V the capacity is 11.9 kA, so verify the available fault current at the point of installation if the system voltage is above 440 V. This unit includes a shunt trip release (STL) for remote tripping via a control signal, which is useful for emergency-stop circuits or supervisory shutdown. The undervoltage release is not fitted, so if undervoltage protection is required, a different variant or an add-on accessory is needed.
Panel integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep, fitting standard 3-pole MCCB panel cutouts. Power loss is 14.6 W maximum, which should be factored into enclosure thermal calculations to avoid exceeding the 70 °C maximum operating temperature.