What it is and what it does
The Siemens SENTRON 3VA2340-5HN42-0JC0 is a 4-pole molded case circuit breaker (MCCB) rated for 4000 A continuous current — that's the full-frame rating, not a derated value — designed for line protection in industrial distribution panels. Breaking capacity reaches 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. That range covers most low-voltage fault scenarios in North American 480Y/277 V and European 400 V systems, with headroom for high-fault utility feeds. Current rating holds flat at 400 A 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 side accordingly.
Built-in accessories and fit
This variant ships with a shunt trip (STL) for remote tripping and two HQ auxiliary switches for status feedback — no undervoltage release, no ground-fault module, no communication function. The basic switch base is 3VA2340-5HN42-0AA0, so the accessory kit is pre-installed at the factory. Maximum power loss is 96 W — account for that in enclosed panel thermal calculations, especially when ganged with other high-current breakers.