What this MCCB is and what the ratings mean for your panel
The Siemens SENTRON 3VA1150-4EE32-0AA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection — it sits at the feeder or downstream subfeed position in a distribution panel, protecting cables and busbars against overloads and short circuits. The TM220 thermal-magnetic trip unit gives it a fixed thermal pickup and a magnetic instantaneous trip that is factory-set, so no field adjustment of the trip curve is needed. At 40 °C it carries 50 A continuously, and the thermal derating is shallow: still 50 A up to 50 °C, then 49 A at 55 °C and 45 A at 70 °C — so in a warm enclosure you lose only 5 A from the 50 A nameplate. The breaking capacity is where this part earns its place: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V. That 121 kA at 240 V means it can interrupt a fault up to that level without the arc flashing over — critical for high-available-fault-current installations like transformer secondaries or large motor control centers.
Physical fit and panel integration
The 3VA1150-4EE32-0AA0 measures 70 mm depth, 76.2 mm width, and 130 mm height. On a DIN-rail or screw-mounted backplate, the 76.2 mm width (roughly 3 inches) means it occupies a standard 3-pole MCCB footprint — no surprises when swapping into an existing SENTRON or third-party panel layout. The front face carries an IP40 protection rating, so it is fine in a typical enclosed panel; keep the front cover on during washdown or dust exposure.