What the ratings mean for fit
The Siemens 3VA1050-4ED32-0KH0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated for line protection duty. Its 50 A continuous current (Iu) holds flat from 40 °C to 50 °C, then derates to 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C — so in a warm panel you lose 5 A by the time ambient hits 70 °C. The breaking capacity is the headline: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. That 121 kA at 240 V means it can interrupt a fault current up to 121,000 A without welding its contacts or venting plasma — critical for high-fault service entrances or transformer-secondaries where the available short-circuit current is massive. The TM210 thermal-magnetic release gives fixed thermal and magnetic trip settings; no adjustment dial, so you size it for the load and leave it. The 70 mm depth, 76.2 mm width, and 130 mm height fit the standard SENTRON 3VA footprint — drops into a panel that was laid out for a 3VA frame without re-drilling the mounting plate. IP40 on the front means it's protected against tools and wires >1 mm entering the breaker face, but the body is not sealed; mount it inside a panel, not in a washdown zone.
Built-in auxiliaries and release options
This MCCB ships with 2 auxiliary switches plus 1 trip alarm switch (HQ version) factory-installed — no separate add-on module to snap in. The shunt trip (STL) is integrated for remote tripping via a control voltage; the integrated auxiliary trip order code is 3VA9688-0BL33 if you need a spare. No undervoltage release, no ground-fault monitoring, no communication module, no phase-failure detection — this is a bare-bones line-protection breaker with just the remote-trip and status-signal capability. Latching endurance is rated at 15,000 operations, which is typical for a distribution MCCB not cycled daily like a contactor.