What this 400 A MCCB delivers
The Siemens SENTRON 3VA2440-6HL32-0JH0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with the ETU320 electronic trip unit handling line protection. The interrupting ratings climb to 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V — so it clears high-fault conditions without cascading upstream in most industrial distribution panels. A shunt trip (STL) is built in for remote emergency-off or undervoltage control loops; the auxiliary contact block carries 2 auxiliary switches plus 1 trip alarm switch (HQ) for status feedback to a PLC or annunciator.
Thermal derating and panel fit
The 400 A rating holds flat from 40 °C through 50 °C, then derates to 384 A at 55 °C, 376 A at 60 °C, 368 A at 65 °C, and 360 A at 70 °C. If the panel ambient runs above 50 °C, size the downstream conductors for the derated figure, not the nameplate. The case dimensions — 248 mm high, 138 mm wide, 110 mm deep — fit standard MCCB cutouts; the 110 mm depth leaves room for rear-access busbars in a 600 mm deep enclosure.
What the ETU320 release controls
The ETU320 is an electronic overcurrent release with adjustable long-time pickup, short-time pickup, and instantaneous settings — no ground-fault or phase-failure detection on this variant. Maximum power loss is 63.5 W, which matters for thermal coordination inside a sealed enclosure. The 15 000 mechanical endurance cycles (latching) suit it for main breaker duty where switching events are infrequent; it is not rated for frequent load-break service.