Ratings and fit for motor switching
The Siemens 3RT2023-2AC20-Z W96 is a SIRIUS power contactor rated AC-3e/AC-3 at 9 A, which translates to 4 kW switching capacity on a 400 V three-phase motor load. For a 4 kW pump or fan at 400 V, this is the sized-to-match choice.
Auxiliary contacts and panel wiring
Built-in 1 NO + 1 NC auxiliary contacts cover basic feedback and interlocking without an add-on block — enough for a starter's hold-in circuit and a status signal back to the PLC. The spring-loaded (cage-clamp) terminals speed up panel wiring: strip 8–10 mm, push the wire in, no screw torque to check. Size S0 footprint (108.5 x 54 x 105.5 mm) fits standard DIN-rail spacing; the multi-unit packaging (18 units per pack) is aimed at panel builders running a batch of identical motor starters.