What it is and what it does
The Siemens 3VA1050-4ED36-0KA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated for line protection, with a shunt trip release (STL) for remote tripping. It carries 50 A continuously at 40 °C ambient, derating to 45 A at 70 °C — the thermal-magnetic trip unit (TM210) handles overload and short-circuit protection without a separate undervoltage release. Breaking capacity is what sets this MCCB apart: 121 kA at 240 VAC, 75.6 kA at 415 VAC, 52.5 kA at 440 VAC, and 11.9 kA at both 500 VAC and 690 VAC. That means it can interrupt fault currents up to those levels without welding contacts or cascading failure upstream — critical for high-fault panels near large transformers or motor control centers.
Panel fit and mounting
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this 3-pole MCCB fits standard SENTRON 3VA panel footprints. The shunt trip adds a control-wire connection alongside the power lugs; verify free-wheeling diode polarity on the trip coil if driving it from a 24 VDC PLC output — the coil suppression is internal but polarity-sensitive. Rated insulation voltage is 800 V, so it handles 480 V and 600 V class systems with headroom. Maximum power loss at rated current is 14.6 W — plan for that heat in a sealed enclosure with multiple breakers ganged together.