The Siemens SENTRON 3VA1150-5EF36-0AF0 is a 3-pole molded case circuit breaker (MCCB) rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release, built for line protection in industrial distribution. It carries a massive 187 kA interrupting capacity at 240 V and 121 kA at 415 V — that means it can safely clear a bolted fault on a 415 V motor control center without the arc flash escalating upstream. In a mining or mill environment where crusher drives and conveyor feeders pile up fault current, this breaker shrugs off the vibration and the fault energy, rated for combustible dust and abrasive slurry.
What the ratings mean for fit
The 50 A continuous rating holds flat from 40 °C to 50 °C — no derate needed in a warm panel. At 55 °C it drops to 48 A, at 60 °C to 47 A, and at 70 °C to 45 A. If your panel ambient sits at 55 °C and the load is 49 A, this breaker is undersized; step up to the next frame. The interrupting curve tells you where this breaker lives: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. At 690 V the available fault current must be under 17 kA — typical for a 690 V mining shovel or conveyor drive, but verify the transformer impedance. The auxiliary contact configuration is 1 auxiliary switch plus 1 trip alarm switch (HQ version). That gives you one NO/NC for status feedback and one dedicated alarm contact that closes only on a trip — essential for a remote SCADA alarm in a mill or pit.
Integration and mounting
The 3VA1150-5EF36-0AF0 measures 76.2 mm wide, 130 mm tall, and 70 mm deep. It mounts on a DIN rail or can be screw-fixed to a backplate. The front face carries an IP40 rating — adequate for a clean indoor panel, but not for washdown. In a mill MCC room with airborne ore dust, IP40 on the front is fine as long as the enclosure itself is sealed.