The Siemens 3VA2340-4HL42-0AA0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) rated for 400 A continuous current across a 40 °C to 50 °C ambient range, with the same 400 A rating holding at those temperatures. The interrupting ratings span from 121 kA at 240 V down to 7.5 kA at 690 V, so this breaker handles high-fault-capacity distribution panels without cascading upstream.
The 400 A rating derates above 50 °C: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. The ETU320 release supports adjustable N-conductor protection: OFF, 50 %, or 100 % of the phase current. That matters for 4-wire distribution where the neutral may carry harmonics or unbalanced return current. Maximum power loss is 96 W — account for that in the panel's thermal budget if the breaker is enclosed with other heat sources.
Dimensions: 248 mm height, 184 mm width, 110 mm depth. The 110 mm depth is the body depth — verify clearance for the front rotary handle and cable lugs in your enclosure. Front-side IP40 protection means it's dust-protected but not sealed against water — suitable for indoor panel mounting, not washdown areas. That covers most unheated electrical rooms and outdoor enclosures in temperate climates.