The Siemens 3RT1023-1BB40-ZX95 is a SIRIUS power contactor in size S0, with a 24 V DC coil and screw-type terminals for the main circuit. It snaps onto a 35 mm DIN rail per DIN EN 50022, occupying 45 mm of panel width. Rated for AC-3 duty at 5.5 kW / 690 V and 4.5 kW / 500 V, it handles motor loads up to those power levels. The AC-4 rating at 400 V is 8.5 A — that's the reversing or inching duty cycle, where the contacts open under full load. Coil draws 5.4 W both on closing and holding — no extra inrush to size your control transformer for. Mechanical life is rated at 10 million cycles, so this contactor will outlast most panel refreshes.
Mounting and Wiring
Mounts via screw or snap-on onto 35 mm standard mounting rail. Side-by-side mounting is allowed with 6 mm clearance to adjacent devices — no forced spacing gaps. Main circuit terminals accept solid conductors up to 2x 4 mm² or stranded up to 2x 10 mm². Control circuit wiring uses 0.5 to 1.5 mm² solid or 0.75 to 2.5 mm² stranded. Pollution degree 3 means it's rated for industrial environments with conductive dust or condensation. Front face carries IP20 protection — safe for finger contact during panel work. The terminal area is IP00, so live parts are exposed; keep the panel door interlocked or use shrouded terminals.