What this MCCB is and what it does
The Siemens SENTRON 3VA1050-3ED32-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated 50 A at 40 °C, designed for line protection in commercial and industrial distribution panels. Its 75.6 kA interrupting capacity at 240 V AC means it can safely clear high-fault currents without upstream device coordination issues — a key parameter for panel builders sizing the main breaker against the service transformer's available fault current.
Key ratings and what they mean for fit
Rated 50 A continuously at 40 °C, with minimal thermal derating: still 50 A at 50 °C, 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That means in a warm enclosure — say a non-ventilated panel near a motor drive — you still get nearly full ampacity without upsizing the frame. Breaking capacity steps down with voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at 500 V and 690 V. For a 480 V distribution board (common in North America), the 32 kA at 440 V is the closest published point — plan your SCCR study around that figure. Insulation voltage rated 800 V, so the breaker is suitable for 690 V systems (typical in European industrial grids) without derating the internal clearances.
Panel integration and wiring
Equipped with a shunt trip (STL) auxiliary release and two auxiliary switches plus one trip alarm switch (HQ). The voltage-trigger function and trip indicator are built in — no external undervoltage release on this variant.