What this MCCB delivers on the line
The Siemens 3VA2340-5HL42-0AG0 is a SENTRON molded case circuit breaker rated for 400 A continuous current at 40 °C, with a 4-pole configuration for three-phase plus neutral line protection. Its interrupting capacity reaches 187 kA at 240 V and 121 kA at 415 V and 440 V, dropping to 75.6 kA at 500 V and 7.5 kA at 690 V — so it handles high-fault utility feeds and transformer secondaries without cascading upstream.
Thermal derating and enclosure planning
The breaker holds its full 400 A rating up to 50 °C ambient. Above that it derates linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If the panel ambient runs hot — say a non-ventilated enclosure near a furnace line — plan the load at the derated figure, not the nameplate. Maximum power loss is 96 W, which adds to the enclosure's thermal budget.
Auxiliary switching and alarm contacts
This variant ships with one auxiliary switch and one trip alarm switch (HP type) built in. The trip alarm signals a fault condition independent of the breaker handle position — useful for remote annunciation on a PLC digital input. No undervoltage release or shunt trip is fitted; those are separate auxiliary release options if the application requires remote tripping.