Siemens 3VA1150-4EF36-0CH0 SENTRON MCCB – 50 A, 3-Pole, 121 kA Breaking Capacity
Its interrupting capacity hits 121 kA at 240 V and 75.6 kA at 415 V — numbers that matter when you're clearing high-fault faults downstream of a transformer or feeding a motor control center. That 50 A rating holds steady through 50 °C, then derates to 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C — so if your panel runs hot near the top of the enclosure, you lose about 1 A per 5 °C above 50 °C. Plan your load margin accordingly.
Key Ratings & What They Mean
The TM240 overcurrent release is a thermal-magnetic trip unit — thermal for overload protection (adjustable), magnetic for short-circuit. That's useful for safety circuits or coordinated shutdown sequences.