What the breaking capacity ratings mean for fit
The Siemens SENTRON 3VA2340-6HL32-0AJ0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, designed for line protection in distribution panels. Its interrupting capacity is the headline selection parameter: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. That 242 kA figure at 240 V means this breaker can safely clear a fault current of that magnitude without welding contacts or rupturing the case — critical for high-fault installations like transformer secondaries or large motor-control centers where available fault current can exceed 100 kA. The 7.5 kA at 690 V still covers most industrial 690 V distribution, but if your system sits at 690 V with fault current above that, this part is not the fit.
Thermal derating and continuous current
The breaker holds its full 400 A rating from 40 °C through 50 °C. Above that, derating is linear: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. In a sealed, uncooled panel with ambient near 60 °C, you lose 7.5 % of the continuous rating — plan the load accordingly. The maximum power loss is 96 W, which factors into enclosure thermal rise calculations. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Auxiliary switching and trip indication
This variant carries 2 auxiliary switches plus 1 trip alarm switch (HP design). The trip alarm signals the breaker's thermal-magnetic or electronic trip event to a PLC or annunciator — useful for remote fault diagnostics. A mechanical trip indicator is present on the front face. There is no undervoltage release and no ground-fault monitoring on this configuration.