What it is and what it does
The Siemens 3RT1016-1AN25-ZX95 is a SIRIUS power contactor in the S00 frame size, designed for switching motor loads in control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, fitting a 45 mm wide slot. Rated 4 kW at AC-2 duty at 400 V and 8.5 A at AC-4 at 400 V, it handles both standard motor starting and plugging/inching applications. The screw-type terminals accept 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded, with a max of 2x 4 mm².
Ratings that matter for fit
AC-2 at 400 V rated at 4 kW covers slip-ring motor starting where the contactor closes and opens under load. AC-4 at 400 V at 8.5 A handles reversing or plugging duty with higher electrical wear. Pollution degree 3 means it's rated for industrial environments with conductive contamination. Operating temperature spans -25 to +60 °C, so it works in unheated enclosures or near process heat. The 45 mm width and 114 mm depth fit standard DIN-rail layouts without crowding adjacent devices.