What this 40 A MCCB does on a line
The Siemens SENTRON 3VA2040-7KQ46-0AA0 is a 4-pole molded case circuit breaker rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. It's designed for line protection (cable and busbar feeder duty), not motor branch circuit protection, so don't spec it for a motor start profile unless you add a separate overload relay. The interrupting ratings are the headline: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3 kA at 690 V. That 330 kA at 240 V is high-end for a 40 A frame — it handles faults on high-capacity transformer secondaries or busway taps without cascading upstream. The adjustable thermal-magnetic trip is set at 16 A initial value, full-scale 40 A, so you dial in the cable protection rather than swapping breaker frames. No undervoltage release or trip indicator on this variant; it does carry a communication function (likely for SENTRON powerconfig or Profibus/Profinet integration) and a ground-fault monitoring version using summation current on L+N.
Panel fit and mounting
Dimensions: 181 mm height, 140 mm width, 86 mm depth. 1.2 W maximum power loss.