What the ratings mean for fit
The Siemens SENTRON 3VA2340-5JQ32-0AA0 is a 3-pole molded case circuit breaker rated for 400 A continuous at 40 °C, with thermal derating to 300 A at 70 °C — the full thermal curve is on the nameplate, so you can size it for a warm panel without guessing. The interrupting capacity reaches 187 kA at 240 V and 121 kA at 415 V, dropping to 75.6 kA at 500 V and 7.5 kA at 690 V; that 690 V figure is the one to check if you are feeding a 690 V drive bus, because the short-circuit current available at that voltage must stay under 7.5 kA or you need a current-limiting upstream device. The adjustable thermal-magnetic trip is set from 80 A to 400 A full scale, so one breaker covers a wide range of feeder sizes. Rated insulation voltage is 800 V, and the breaker includes ground-fault monitoring via summation current formation on the L-conductor — useful for detecting leakage on ungrounded or resistance-grounded systems without a separate GFCI module. Communication function is onboard, so it can integrate with a higher-level monitoring system for trip events and load data.
Deployment context
Mounts in a standard switchboard or panel enclosure on a DIN rail or direct-mount plate — the 110 mm depth and 138 mm width fit typical distribution sections. The 248 mm height means it occupies three full 9 mm module spaces on a DIN rail, so factor that into your panel layout. Maximum power loss is 96 W at rated current, which adds to the enclosure's thermal load; ensure adequate ventilation or forced cooling if the panel is densely packed.