Line protection MCCB with TM210 release
The Siemens SENTRON 3VA1050-4ED42-0AC0 is a 4-pole molded case circuit breaker rated for line protection duty, carrying a rated continuous current Iu of 50 A and a rated insulation voltage Ui of 800 V. The interrupting ratings are specified per the datasheet: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V — these are the fault-clearing capacities at those system voltages, so the breaker can be applied across a wide range of supply configurations without upstream reinforcement. The overcurrent release is a TM210 thermal-magnetic type, which means the thermal element handles overload protection and the magnetic element handles short-circuit protection — no electronic adjustment, no communication module, no ground-fault monitoring. The breaker carries 2 auxiliary switches (HQ version) for remote status indication, but no undervoltage release, no voltage trigger, and no phase-failure detection are fitted.
Thermal derating and panel integration
The 50 A rating holds flat from 40 °C through 50 °C ambient. Above that, the continuous current must be derated: 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 is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The front face carries an IP40 protection class — suitable for dry indoor panel environments, not for washdown or outdoor exposure. Physical dimensions: 70 mm depth, 101.6 mm width, 130 mm height. The 4-pole footprint matches the standard SENTRON 3VA frame, so it mounts directly on the DIN rail or panel-mount plate without adapter brackets. The latching endurance is rated at 15 000 operations — a figure that governs the mechanical life under normal switching, not the electrical endurance under fault conditions.