What it is and what it does
The Siemens 3VA1050-4ED42-0JH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection in distribution panels. It carries a rated continuous current Iu of 50 A across four poles, with a rated insulation voltage Ui of 800 V — meaning it handles 400 V three-phase distribution without issue and has headroom for 690 V applications where the breaking capacity still holds at 11.9 kA. Breaking capacity is 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V — figures that cover most industrial low-voltage fault levels downstream of a transformer. The 50 A frame is thermally rated; it holds full current up to 50 °C ambient, then derates to 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. In a cement plant control room that hits 55 °C in summer, you lose 2 A — not enough to nuisance-trip a 45 A motor feeder, but worth knowing if you're running right at the limit.
Configuring the trip and auxiliary package
This variant ships with a TM210 thermal-magnetic overcurrent release — fixed thermal and magnetic settings, no electronic adjustment. The auxiliary contact block is a 2 auxiliary switches + 1 trip alarm switch HQ configuration (three discrete signals: breaker open/closed, and a separate alarm that fires only on a trip event). A shunt trip release (STL) is integrated for remote opening; the integrated auxiliary trip order code is 3VA9688-0BL32. No undervoltage release, no communication module, no ground-fault monitoring on this SKU. The front face carries a voltage-trigger indicator and a mechanical trip indicator — so when you walk the panel after a fault, you see a red flag without needing a meter. IP40 on the front means it's protected against tools and wires >1 mm, but not sealed against dust; in a cement plant environment, mount it inside a gasketed enclosure or the kiln dust will find its way into the mechanism over time.
Panel fit and wiring
Dimensions: 70 mm deep, 101.6 mm wide, 130 mm tall. The 101.6 mm width is a standard 4-pole MCCB footprint — it occupies four 25.4 mm (1-inch) module positions on a DIN rail or mounting plate. Depth of 70 mm means it clears a 120 mm deep enclosure with room for rear-connected busbars. Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C, so it can sit in an unheated warehouse through winter without damage.