What this breaker is and what the ratings mean
The Siemens 3VM1140-3EE46-0AA2 is a 4-pole IEC circuit breaker from the 3VM1 frame family, rated at 160 A frame size with a breaking capacity class N — 25 kA at 415 V. That 25 kA Icu means it can safely interrupt a fault current up to 25,000 amps without welding or rupturing, which is the standard for most industrial distribution panels in a 415 V system. The In=40 A sets the continuous current rating, and the TM220 thermal-magnetic trip unit gives you adjustable overload protection from Ir=28 A up to 40 A, plus a fixed short-circuit pickup at 10 times In (400 A). This lets you fine-tune the overload to match the actual load cable ampacity, not just the breaker frame.
Where it fits and how it connects
This breaker mounts on a standard DIN rail inside a panel — common for IEC switchgear layouts. The 4-pole configuration (three phases plus a switched neutral) is typical for TT or TN-S systems where you need to break the neutral for isolation. Terminal connections are for copper or aluminum conductors, sized per the terminal spec.