The Siemens SENTRON 3VA2340-5HN42-0JH0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in distribution panels. Its interrupting capacity reaches 187 kA at 240 VAC and 121 kA at 415/440 VAC, tapering to 7.5 kA at 690 VAC — the 690 V figure governs the high-voltage end of the fault-current curve and is the one to check for 600 V class systems. The breaker includes a shunt trip (STL) release and 2 auxiliary switches plus a trip alarm switch (HQ), so it fits remote-trip and status-monitoring circuits without adding external relays.
Sizing and thermal derating
The 400 A rating holds at ambient temperatures up to 50 °C. 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 at 60 °C, the breaker effectively carries 370 A — plan the load side accordingly. Maximum power loss is 96 W, which matters for heat buildup in a sealed enclosure.
Physical fit and panel integration
Dimensions: 248 mm high, 184 mm wide, 110 mm deep. The 110 mm depth is the dimension from the mounting surface to the front cover — important when the panel door clearance is tight. The breaker mounts on a DIN rail or directly to a backplate; the 4-pole body is wider than a 3-pole, so verify the enclosure cutout or busbar spacing before committing the BOM.