It uses spring-loaded terminals for the auxiliary and control circuit wiring, accepting 2x (0.5... 1.5 mm²) with core end processing or 2x (0.5... 2.5 mm²) without. The block is noted for use with 3RT1 contactors, extending the auxiliary contact count on the power contactor or contactor relay.
The contacts are rated for a maximum of 10 A, with specific current ratings at various voltages: 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, 6 A at 250 V, 3 A at 400 V, and 0.3 A at 220 V. For DC switching, the rated values are 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. The AC-15 rating at 690 V is 1 A, which governs the switching of inductive loads like contactor coils at that voltage. The surge voltage resistance is rated at 6 kV, and the insulation voltage at AC with degree of pollution 3 is 690 V.
This part is a phased-out product. The official successor is the SIRIUS 3RH2 series. The successor, 3RH2122-2BG40, is a direct-form-fit replacement with spring-loaded terminals and the same contact configuration (2 NO + 2 NC), but note the depth increases from 51 mm to 73 mm and width from 44 mm to 45 mm, so panel layout should be verified before substitution.
The block is 51 mm deep, 44 mm wide, and 38 mm tall, so it fits within the standard S00 contactor footprint.