Built-in phase failure detection ensures the breaker trips if one phase drops out — critical for preventing single-phasing damage on three-phase motor loads.
At 400 V AC the 3RV1021-1KA38-1KT1 delivers 100 kA breaking capacity, matching the 3RV1011-1HA10's 100 kA at 400 V — so in a panel originally specified around the 1HA10, this unit drops into the same fault-current coordination zone without recalculating arc-flash limits.
Width is 45 mm — one standard module — so it fits a 9-module row with room for a contactor and overload alongside. Screw-type terminals on the main circuit accept 2x (0.25…2.5 mm²) solid or 2x (24…14 AWG) stranded. The auxiliary switch is transverse-mounted and included as standard.