What this 400 A MCCB delivers
The Siemens SENTRON 3VA2340-5HL42-0DA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with no derating needed up to 50 °C — at 55 °C it still carries 385 A, and at 70 °C it holds 340 A. Breaking capacity reaches 187 kA 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 utility feeds and large motor branch circuits without cascading upstream. The built-in undervoltage release (UVR) trips the breaker when control voltage drops, which is standard for emergency-stop and safety isolation circuits in industrial panels.
Panel fit and dimensions
The breaker measures 248 mm high, 184 mm wide, and 110 mm deep — a standard footprint for this current class. It mounts via the SENTRON base plate or directly on a DIN rail adapter (not included). The 110 mm depth leaves clearance for rear-connected busbars in a typical 400 mm deep enclosure.
Power loss and thermal management
Maximum power loss is 98.5 W at rated current. In a sealed panel with multiple breakers, that heat needs to be factored into the enclosure's dissipation budget — especially if the breaker is continuously loaded near 400 A.