400 A MCCB with adjustable trip and high interrupt rating
The Siemens SENTRON 3VA2340-6KP32-0JL0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with an adjustable thermal-magnetic trip unit spanning 600 A to 4 000 A. That trip range means this single frame covers feeder protection from moderate loads up to the full 4 kA — useful for a panel where future load growth is expected and you want one breaker to handle both the initial and expanded draw without a frame swap. Breaking capacity is 242 kA at 240 V, 187 kA at 415 V, 187 kA at 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. At 415 V — typical for industrial distribution in much of the world — the 187 kA rating places this breaker well above the available fault current on most service entrances, so it can be used as the main without worrying about cascading failure upstream.
Built-in communication and auxiliary switching
This variant includes a communication function and other measurement functions, meaning it can report status and metering data over the bus — useful for a plant-wide power monitoring scheme where you want to see load current, trip events, and power quality from the central SCADA without adding external CTs or I/O modules. A shunt trip release (STL) is also built in, allowing remote tripping from an E-stop or fire alarm system.
The 70 °C operating ceiling is the internal air temperature around the breaker, not the ambient in the room — in a hot panel near a furnace or in a Middle Eastern substation, derate the continuous current per the thermal curve (at 70 °C, the 400 A rating drops to 300 A per the spec table). Maximum power loss is 96 W. In a sealed, non-ventilated enclosure with multiple breakers, that heat adds up — account for it in the thermal design of the panel to avoid nuisance tripping on high ambient.