Line protection MCCB with high interrupting capacity
The Siemens 3VA1140-4EF32-0CC0 is a 3-pole SENTRON molded case circuit breaker rated 40 A continuous current, built for line protection in distribution panels. Its TM240 thermal-magnetic release provides overload and short-circuit protection, with a fixed thermal curve and magnetic trip calibrated for cable and busbar protection. The interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 440 V — enough to handle high-fault utility feeds without cascading upstream. At 690 V the rating drops to 11.9 kA, still adequate for most industrial motor branch circuits. The breaker includes an integrated undervoltage release (UVR) and two HQ auxiliary switches for status feedback to a PLC or annunciator. No communication module, phase-failure detection, or ground-fault monitoring is built in — this is a straightforward line-protection device, not a power-monitoring breaker. The auxiliary trip is ordered separately as 3VA9608-0BB24.
Thermal derating and panel integration
The breaker holds its full 40 A rating from 40 °C up to 50 °C ambient. Above that, derating is gradual: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. In a sealed enclosure or high-ambient panel, size the load circuit for the derated value, not the nameplate. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a standard 3-pole MCCB footprint for DIN-rail or screw-mount panel integration. The front face carries IP40 protection, suitable for dry indoor enclosures. No trip indicator is fitted, so visual status relies on the auxiliary switches or handle position.