What this breaker is and what it does
The Siemens SENTRON 3VA2340-5HN42-0DC0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. It carries a 187 kA breaking capacity 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 handles high-fault-current service entrances and main feeders without cascading upstream. The 400 A rating holds at ambient temperatures up to 50 °C without derating; above that it steps down 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 runs hot — say, a non-ventilated enclosure near a furnace line — size for the derated figure, not the nameplate.
Built-in auxiliaries and releases
This variant ships with an undervoltage release (UVR) and two auxiliary switches (HQ design). The UVR trips the breaker when control voltage drops below a threshold — standard for emergency-stop chains or undervoltage protection on motor feeders. No ground-fault monitoring module is fitted from the factory, so if you need GF protection that has to be added externally. The breaker does not include a communication module or voltage-trip indicator, and there is no trip-indicator flag on the front. For remote status you rely on the auxiliary switches wired back to a PLC input.
Panel fit and environment
Dimensions are 248 mm high, 184 mm wide, 110 mm deep — a standard SENTRON 3VA2 frame footprint. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss at rated current is 98.5 W, so account for that heat in your enclosure sizing.