Line protection MCCB with 121 kA interrupting capacity at 240 V
The Siemens 3VA1140-4EF32-0HC0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection in three-phase distribution. It carries a continuous current Iu of 40 A and a rated insulation voltage Ui of 800 V, with a TM240 thermal-magnetic overcurrent release. The interrupting capacity reaches 121 kA at 240 V and 75.6 kA at 415 V, which means it can safely clear high-fault currents on the secondary side of a distribution transformer without upstream fuse coordination failure.
Thermal-magnetic curve and derating across temperature
The TM240 release holds a full 40 A from 40 °C through 50 °C ambient. Above that, derating begins: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. If the panel ambient runs above 50 °C, the continuous load must be reduced accordingly to avoid nuisance tripping.
Shunt trip and auxiliary contacts for remote control
This MCCB includes a shunt trip (STL) for remote undervoltage or emergency-off tripping, plus two auxiliary switches HQ for status feedback to a PLC or annunciator panel. The auxiliary release order code is 3VA9688-0BL30. No undervoltage release or ground-fault monitoring is fitted on this variant.
Physical fit and panel integration
Dimensions are 130 mm height, 76.2 mm width, and 70 mm depth. The 3-pole footprint is standard for a 160 A frame MCCB; it mounts on a DIN rail or directly to a backplate. Front IP40 protection means it is suitable for enclosed panels but not for washdown zones.