Siemens 3VA1150-5EF32-0HA0 — 50 A MCCB with TM240 Release and Shunt Trip
It carries a continuous current rating of 50 A at 40 °C, with minimal thermal derating up to 70 °C (45 A at 70 °C). The TM240 thermal-magnetic release provides fixed overload and short-circuit protection curves, while the integrated shunt trip (STL) allows remote tripping for emergency-off or supervisory control circuits. Breaking capacity is the headline number here: 187 kA at 240 V AC, stepping down to 121 kA at 415 V and 75.6 kA at 440 V. That SCCR headroom means this breaker can sit upstream of a high-fault panel without cascading — useful for industrial switchboards where the transformer rating drives available fault current above 100 kA.
The shunt trip (STL) auxiliary release requires a separate control voltage — verify polarity and free-wheel diode on the coil before energizing. Maximum power loss is 14.6 W, so ventilation in a sealed enclosure is advisable if multiple breakers are ganged.