What this MCCB is and where it fits
The Siemens 3VA1150-6EF36-0AD0 is a SENTRON molded case circuit breaker designed for line protection — the primary overcurrent protection in distribution panels, switchboards, and motor control centers. Three poles, rated 50 A at 40 °C, with a TM240 thermal-magnetic trip unit. The 70 mm depth and 76.2 mm width match the standard 3VA mounting footprint, so it drops into existing SENTRON panel layouts without re-drilling the backplate.
Breaking capacity — what the numbers mean for your fault level
This breaker carries 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. Those are the maximum fault currents it can safely interrupt at each voltage — critical for selectivity studies. If your available fault current at the panel is, say, 65 kA at 415 V, this breaker gives you 89 kA of headroom above that, so it coordinates cleanly with downstream devices without cascading failure.
Current derating — the real ampacity in a warm panel
Rated 50 A from 40 °C through 50 °C, then it starts to taper: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, 45 A at 70 °C. That derating curve is the one to size against if your enclosure runs hot — don't just use the 50 A nameplate. The 14.6 W maximum power loss also needs to be factored into the enclosure thermal budget, especially in a sealed cabinet.