What this MCCB delivers on the line
The Siemens SENTRON 3VA1150-3EF32-0DC0 is a 3-pole molded case circuit breaker rated for 50 A continuous current. Its interrupting capacity hits 75.6 kA at 240 V and 52.5 kA at 415 V — enough to handle high-fault utility feeds or transformer secondaries without cascading upstream. The TM240 thermal-magnetic release gives fixed thermal and magnetic trip settings, so it's a straight swap for existing 50 A line-protection duty in distribution panels or motor control centers. At 70 mm deep, 76.2 mm wide, and 130 mm tall, this MCCB fits standard SENTRON 3VA panel footprints. The IP40 front rating means it's fine for indoor enclosures; no special sealing needed for the switchboard face.
Thermal derating and real-world current
The 50 A rating holds flat from 40 °C up to 50 °C. Above that it derates: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the panel ambient runs hot — say next to a drive or transformer — size the upstream protection for the derated value, not the nameplate 50 A.
Built-in undervoltage release and auxiliary contacts
This version ships with an undervoltage release (UVR) as the auxiliary release design. That means the breaker trips if control voltage drops below the dropout threshold — useful for safety circuits or to prevent automatic reclosure after a brownout. It also carries 2 auxiliary switches HQ (high-qualified) for remote status indication. The integrated auxiliary trip uses order code 3VA9608-0BB25 for replacement. There is no communication module, no phase failure detection, and no ground fault monitoring on this variant. It's a straight line-protection breaker — no bells, no onboard metering. If you need those, you're looking at a different 3VA option.