What it is and what it does
The Siemens 3VA1150-6EF32-0KC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in industrial distribution panels. It's a 3-pole unit rated 50 A at 40 °C, with a rated insulation voltage of 800 V — so it handles standard 400/480 VAC buswork with margin.
Breaking capacity — the real number for fault duty
At 240 VAC this breaker interrupts 220 kA; at 415 VAC it's 154 kA, and at 440 VAC it's 121 kA. Those are high-end figures — this is a current-limiting MCCB sized for high-fault installations like transformer secondaries or large motor control centers. At 500 V and 690 V the rating drops to 17 kA, so verify your system voltage against the curve before specifying.
Thermal derating — don't oversize the frame
The breaker holds a full 50 A from 40 °C up to 50 °C. Above that it derates: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If your panel ambient runs above 50 °C, factor that into the load schedule — the frame won't trip early, but continuous current capacity drops.
Built-in auxiliaries and release
This variant ships with a shunt trip (STL) for remote opening and two auxiliary switches HQ (form C) for status feedback to a PLC or annunciator. No undervoltage release, no ground-fault monitoring — that's by design for line-protection duty where the shunt trip is the primary remote-control path.