The Siemens 3RT1023-1AP00-ZX95 is a SIRIUS power contactor in the S0 frame size, built for switching three-phase motor loads up to 5.5 kW at 690 V (AC-3 duty) or 4.5 kW at 500 V. It carries three normally-open main contacts and a 230 V 50 Hz coil. The front face is rated IP20, meaning it's touch-safe once installed in an enclosure; the terminals themselves are IP00, so they need to be inside a panel or glanded box.
The body is 45 mm wide, 85 mm tall, and 91 mm deep — that's a standard S0 footprint, so it fits into the same slot as any other S0 contactor in the SIRIUS family.
Wiring and terminal details
Main circuit terminals are screw-type, accepting solid conductors from 2x 0.5 to 1.5 mm² up to a maximum of 2x 4 mm², and stranded conductors from 2x 1 to 2.5 mm² up to 2x 10 mm². In AWG that's 2x 16–12 solid, 2x 14–10 stranded, or a single 8 AWG. The coil terminals take the same range.
Switching capacity and coordination
For motor starting (AC-3), the contactor is rated 5.5 kW at 690 V and 4.5 kW at 500 V. For AC-4 duty (plugging/reversing), it handles 8.5 A at 400 V. For resistive loads (AC-12), the maximum operating current is 10 A. The auxiliary contact ratings cover 24 V at 10 A, 60 V at 2 A, 110 V at 1 A, 220 V at 0.3 A, 230 V at 6 A, and 400 V at 3 A. Type 1 coordination requires a 63 A gL/gG fuse; Type 2 coordination requires a 25 A gL/gG fuse. That's the fuse size you need to protect the contactor in a short-circuit scenario — pick the one that matches your coordination philosophy.