What it is and what it does
The Siemens 3VA2340-5HL42-0KA0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, with a four-pole configuration and a shunt trip release (STL) for remote tripping. It is designed for line protection — meaning it guards feeders and main distribution against overloads and short circuits, not motor or generator protection. The interrupting ratings are serious: 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 — so it can handle high-fault utility feeds without cascading upstream.
Thermal derating and sizing
The breaker holds full 400 A up to 50 °C ambient. Above that it derates: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel runs hot, size the load side accordingly. Maximum power loss at rated current is 96 W — a factor for enclosure heat rise calculations, especially in sealed or high-density panels.
Physical fit and panel integration
Dimensions are 248 mm high, 184 mm wide, and 110 mm deep — a standard 4-pole MCCB footprint that fits most DIN-rail or panel-mount backplates without re-drilling. It ships without auxiliary switches or undervoltage release; the only auxiliary release is the shunt trip (STL). If you need a UVR or ground-fault module, this variant doesn't carry them.