The Siemens SENTRON 3VA2340-5JQ42-0JC0 is a 4-pole molded case circuit breaker (MCCB) rated 400 A continuous at 40 °C, designed for line protection in distribution panels. Its interrupting capacity hits 187 kA at 240 V and 121 kA at 415 V — enough headroom for high-fault service-entrance or sub-distribution boards where SCCR compliance is tight. The 110 mm depth and 184 mm width fit standard SENTRON mounting patterns; the integrated communication function allows remote trip indication and load monitoring without an add-on module.
Ratings and what they mean for the panel
The 400 A full-scale rating holds flat from 40 °C through 50 °C — no derating needed in a warm enclosure. At 55 °C it drops to 375 A, at 60 °C to 350 A, and at 70 °C to 300 A. That thermal curve is the real selection gate: a panel that runs at 55 °C ambient loses 25 A of headroom. The 4 000 A maximum short-time rating and 600 A minimum let you coordinate selectively with downstream breakers, keeping a faulted branch from taking the whole board dark. Interrupting capacity drops sharply above 500 V: 75.6 kA at 500 V, then 7.5 kA at 690 V. On a 690 V line this breaker is only good for low-fault locations — verify the available fault current before committing the BOM. Power loss is 96 W maximum at rated load. That's heat that stays in the enclosure; factor it into the thermal budget if the panel is densely packed.
Integration and accessories
The breaker ships with two HQ auxiliary switches and a shunt trip (STL) release factory-installed. The 110 mm depth and 248 mm height fit the SENTRON mounting footprint — no panel rework if you're replacing a 3VA2 frame. The undervoltage release is not fitted, so if UVR is required for your safety circuit, order that variant or add the release separately. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing, not running conditions.