400 A MCCB with ETU320 — what the ratings mean for your panel
The Siemens 3VA2340-5HL32-0JH0 is a SENTRON molded case circuit breaker rated for a continuous current Iu of 400 A, with an ETU320 electronic trip unit handling line protection across a 3-pole configuration. Breaking capacity hits 187 kA at 240 V AC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V — so at typical 400 V distribution voltages this breaker clears faults up to 121 kA without cascading upstream devices. That 187 kA at 240 V matters for high-fault panels close to the transformer secondary; the 17 kA at 690 V still covers most industrial motor circuits at that voltage class.
Temperature derating and power loss — plan the enclosure
At 40 °C, 45 °C, and 50 °C ambient the breaker carries the full 400 A without derating. At 55 °C it drops to 385 A, at 60 °C to 370 A, at 65 °C to 355 A, and at 70 °C to 340 A. Maximum power loss is 96 W — that heat has to leave the enclosure, so factor it into the thermal budget for a sealed or high-fill panel. Dimensions are 248 mm high, 138 mm wide, 110 mm deep, which fits standard SENTRON 3VA2 mounting footprints; verify the gland-plate cutout against the existing backpanel if retrofitting.
Integrated accessories — shunt trip and auxiliary switches
Factory-fitted with a shunt trip (STL) design for remote tripping and a 2-auxiliary + 1 trip-alarm switch HQ configuration. The shunt trip allows a PLC or E-stop circuit to open the breaker without a manual action — common in safety circuits and remote shutdown schemes. The auxiliary contacts report breaker position back to the control system; the separate trip alarm signals a fault trip distinct from a manual open. No undervoltage release, no communication module, no ground-fault monitoring on this variant.