What it is and what it does
The Siemens SENTRON 3VA1140-4EF32-0AC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection in distribution panels. It carries a continuous current of 40 A at 40 °C, with minimal derating up to 70 °C (37 A at 70 °C). The TM240 thermal-magnetic release provides overload and short-circuit protection, with a fixed thermal element and a magnetic trip calibrated for the 40 A frame.
Breaking capacity — what the numbers mean
Rated breaking capacity reaches 121 kA at 240 V AC, dropping to 75.6 kA at 415 V AC, 52.5 kA at 440 V AC, and 11.9 kA at 500/690 V AC. These are the maximum fault currents the breaker can safely interrupt at each voltage level. For a 400 V distribution board, the 75.6 kA figure gives substantial headroom above typical utility fault levels, making it suitable for high-fault installations like industrial substations or large motor control centers.
Fit and mounting — panel integration
Measuring 76.2 mm wide, 130 mm high, and 70 mm deep, this MCCB fits standard 3-pole MCCB footprints. It mounts on a DIN rail or directly to a panel backplate via the integral mounting clips. The 70 mm depth keeps it within typical enclosure depths for 200–400 A rated switchboards.