What this MCCB is and what it does
The Siemens 3VA1050-2ED42-0HH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — meaning it sits on the feeder side of a panel, protecting cables and busbars from overcurrent and short-circuit faults. It carries a rated current of 50 A at 40 °C and holds that rating through 50 °C before starting to derate: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That thermal curve means an enclosure with marginal airflow at 55 °C still gets 49 A of continuous duty. Breaking capacity is 52.5 kA at 240 V, 32 kA at 415 V, 13.6 kA at 440 V, and 7.5 kA at both 500 V and 690 V. The 52.5 kA figure at 240 V is high enough for most industrial service-entrance applications where fault current is substantial. Rated insulation voltage is 800 V, so the breaker can be used on 480/277 V and 600/347 V systems with margin. This is a 4-pole MCCB — it switches all three phases plus neutral, which is required for some distribution schemes where the neutral must be protected (e.g., TN-S systems with a switched neutral). The unit includes a shunt trip release (STL) for remote tripping and comes with two auxiliary switches plus one trip alarm switch (HQ) for status feedback to a PLC or annunciator panel.
Panel fit and integration
The breaker measures 70 mm deep, 101.6 mm wide, and 130 mm tall. The 101.6 mm width (4 inches) is the standard 4-pole MCCB footprint for this class — it occupies four 25 mm (1-inch) module spaces on a DIN rail or mounting plate. Depth of 70 mm means it clears most standard enclosure gland plates and backpanels without interference. Maximum power loss is 14.6 W. In a sealed enclosure with multiple breakers ganged together, that heat adds up — account for it in the thermal budget. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C.
What the ratings mean for your decision
The 50 A rating at 40 °C is the continuous current the breaker can carry without tripping. If your panel ambient is higher than 40 °C, use the derated values: at 60 °C you lose 2 A (48 A), at 70 °C you lose 5 A (45 A). The 52.5 kA interrupting rating at 240 V means this breaker can safely clear a fault with that much available current — important for service-entrance or main-breaker positions near a transformer. At 690 V the same breaker still interrupts 7.5 kA, which covers most motor branch circuits at that voltage level. Shunt trip (STL) for remote tripping. Two auxiliary switches and one trip alarm switch (HQ) for status feedback.