The Siemens 3RV2331-4DC10 is a SIRIUS-brand circuit breaker designed specifically for starter combinations. It interrupts fault currents up to 30 kA at 400 V and 100 kA at 240 V — the 30 kA figure is the one that governs selectivity in a 400 V distribution panel; the 100 kA at 240 V covers high-fault utility feeds. Width is 55 mm, depth 149 mm, height 140 mm. The 55 mm width is a single modular unit — it occupies one 55 mm slot on the DIN rail, leaving adjacent space for contactors or auxiliaries. That 50 mm vertical clearance is the one that catches panel builders who crowd the rail — the arc-chamber venting needs that gap.
Main circuit connections use screw-type terminals. The terminal accepts solid or stranded copper: 2x (1 to 25 mm²) or 1x (1 to 35 mm²). Main contact terminal size is M6. For a panel wireman, the 35 mm² single-conductor capacity means it handles the full rated current without needing a ferrule or pin terminal — just strip and torque to the M6 spec.
The breaker does not include ground-fault or phase-failure detection; those functions are handled externally by the upstream protection or the motor starter combination.