Line protection MCCB with TM210 release
The Siemens SENTRON 3VA1050-4ED32-0KC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection duty, carrying a rated continuous current Iu of 50 A and a rated insulation voltage Ui of 800 V. Its TM210 thermal-magnetic overcurrent release provides fixed thermal and magnetic trip settings, making it a straightforward choice for feeder or branch-circuit protection in distribution panels. The 121 kA breaking capacity at 240 V AC means it can safely interrupt very high fault currents without upstream fusing — useful at main switchboard entries or near large transformers where available fault current is high. At 415 V the interrupting rating is 75.6 kA, and at 690 V it drops to 11.9 kA, so verify the system voltage against the site's available fault current before specifying.
Current derating and thermal limits
This MCCB holds its full 50 A rating from 40 °C up to 50 °C ambient. Above that, derating begins: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. The operating temperature range spans -25 °C to 70 °C, with storage from -40 °C to 80 °C. For panels running warm — near drives or transformers — the 55 °C derating step is the first one that matters for sizing.
Integrated accessories and auxiliary contacts
The breaker ships with a shunt trip (STL) release integrated, part number 3VA9688-0BL33 for the auxiliary trip assembly. Two HQ auxiliary switches are built in — these provide status feedback (open/closed/tripped) to a PLC or indication lamp without needing a separate auxiliary contact block. There is no undervoltage release, no ground-fault monitoring, no phase-failure detection, and no communication module, so this is a pure line-protection device with remote trip capability via the shunt release. The front face carries IP40 protection — suitable for enclosed panel mounting, not for washdown environments.
Physical fit and panel integration
Dimensions: 130 mm height, 76.2 mm width (3-pole standard), 70 mm depth. The width matches the standard 3-pole MCCB footprint for DIN-rail or screw-mount panel installation. No trip indicator on the front — status is read from the auxiliary switches or the handle position. The shunt trip wiring must be run separately; verify polarity for the STL coil before energizing.