What it is and what it does
The Siemens SENTRON 3VA2340-6JP42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in industrial power distribution. It carries a maximum breaking capacity of 242 kA at 240 V and 187 kA at 415 V, which means it can safely interrupt fault currents up to those levels without upstream devices needing to trip — critical for maintaining selectivity in a multi-level panel. The ETU550 electronic trip unit provides adjustable protection curves, and the breaker includes a communication function for integration with monitoring systems — useful for a plant-floor electrician who wants to see trip events logged without walking the panel.
Thermal derating and real-world current
The 400 A rating holds from 40 °C up to 50 °C ambient. Above that it derates: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel runs hot — say a packed enclosure near a furnace line — the 60 °C figure is the one to size against, not the nameplate 400 A.
Mounting and panel fit
Dimensions: 248 mm high, 184 mm wide, 110 mm deep. The 184 mm width for a 4-pole frame is standard for this class — it will drop into a panel cutout designed for a SENTRON 3VA2 4-pole without rework. IP40 on the front means it's fine for a dry indoor enclosure; no washdown rating here.