What this breaker is and what it handles
The Siemens SENTRON 3VA2340-5HL42-0KC0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels and switchboards. It carries a maximum interrupting rating of 187 kA at 240 V, dropping to 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so the SCCR you need at your system voltage decides the fit, not just the headline number. The breaker holds its full 400 A rating from 40 °C through 50 °C, then derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel ambient runs above 50 °C, size the load to the derated curve — not the nameplate. It ships with a shunt trip release (STL) and two auxiliary switches (HQ type), so it's ready for remote trip and status feedback without adding modules. No undervoltage release, no ground-fault monitoring, and no communication function — this is a straightforward line-protection breaker, not a smart metering device.
Physical footprint and panel fit
The 3VA2340-5HL42-0KC0 measures 248 mm high, 184 mm wide, and 110 mm deep. That 110 mm depth (4.33 in) is the dimension that matters for enclosure depth — make sure your gland plate or back panel leaves enough clearance for the breaker body and cable bends. Maximum power loss is 96 W at rated current, so factor that into your enclosure thermal budget if the panel is tightly packed.