What it is and what it does
The Siemens 3VA1050-2ED42-0BH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a 50 A continuous rating at 40 °C ambient, with a 4-pole configuration covering all phases plus neutral. The interrupting capacity reaches 52.5 kA at 240 V AC, 32 kA at 415 V, 13.6 kA at 440 V, and 7.5 kA at both 500 V and 690 V — so the same breaker can be specified across multiple voltage levels without swapping frame sizes. Rated insulation voltage is 800 V, giving headroom for 690 V systems. The breaker includes an undervoltage release (UVR) and comes pre-fitted with 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). That means it can signal its status back to a PLC or safety relay without adding a separate accessory module. A mechanical trip indicator is standard, so a quick panel walk-down confirms whether the breaker has tripped without opening the door.
Thermal derating and panel fit
The 50 A rating holds flat from 40 °C to 50 °C, then drops to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the panel ambient runs above 50 °C, size the load at the derated value — not the nameplate 50 A. Maximum power loss is 17.1 W, which adds to the enclosure's thermal budget. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Dimensions are 130 mm high, 101.6 mm wide, 70 mm deep. The 70 mm depth is shallow enough for most 200 mm deep enclosures; the 101.6 mm width (4 inches) occupies a standard MCCB footprint on the DIN rail or mounting plate. No communication module or ground-fault monitoring is built in — this is a straight line-protection breaker with aux contacts and UVR.