Siemens 3RT1023-1AP04-1AA0 — SIRIUS S0 Power Contactor, 3 NO, Screw Terminals
The Siemens 3RT1023-1AP04-1AA0 is a SIRIUS-brand power contactor in the S0 frame size, designed for switching three-phase motor loads and resistive loads in industrial control panels. It carries 3 normally-open main contacts and is rated for 4.5 kW at 500 V and 5.5 kW at 690 V, making it suitable for 400 V class motors in European and export panels. The AC-4 rating of 8.5 A at 400 V covers demanding reversing or plugging duty cycles where the contactor makes and breaks stalled-rotor current. Mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, occupying 45 mm of panel width. The 85 mm height and 140 mm depth fit standard S0 enclosure cutouts. Front face carries IP20 finger-safe protection; the terminal area is IP00, so keep live parts behind a panel door or shrouding.
Termination and Wiring
Main circuit terminals are screw-type, accepting 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), or max 2x (0.75–4 mm²) solid conductors. For stranded wire, the range is 2x (1–2.5 mm²), 2x (2.5–6 mm²), or max 2x 10 mm². AWG equivalents: 2x (16–12), 2x (14–10), or 1x 8. The auxiliary contact block (2 instantaneous contacts) uses the same screw-clamp system. Strip length and torque follow standard S0 terminal specs — no special tooling needed.
Coordination and Protection
For Type 2 coordination (no damage to the contactor under short circuit), the required upstream fuse is gL/gG 25 A. For Type 1 coordination (contactor may need replacement after fault), use gL/gG 63 A. The pollution degree 3 rating means it tolerates conductive dust and humidity typical of industrial enclosures without conformal coating. Maximum operating altitude is 2,000 m without derating.