The 3RV1021-0EA10: The 690 V operating voltage covers most three-phase industrial supplies up to 690 V line-to-line — common in European and some North American heavy-industrial installations. The surge voltage resistance of 6000 V gives it a rated impulse withstand that matches typical IEC 60947-2 coordination levels for distribution boards — so it can handle the transient spikes from nearby switching without nuisance tripping or damage.
The screw and snap-on mounting onto 35 mm DIN rail per EN 50022 is the same footprint used by the SIRIUS contactor family (e.g., 3RT1016-1AR11, 3RT1016-1AG61, 3RT1023-1AL20). So if you're replacing a contactor with a motor-protective circuit breaker or adding one upstream, it clips onto the same rail without extra brackets. The 10.6 cm x 5.5 cm x 10.7 cm dimensions leave room for side-by-side mounting with adjacent devices — no special spacing required for standard coordination.