What it is and what it does
The Siemens 3RT1015-2BF42 is a SIRIUS power contactor in the S00 frame size, designed for switching motor loads in industrial control panels. It carries a 110 VDC coil and uses spring-loaded terminals for the main current circuit, which means no screw torque verification on the line — just strip, insert, and seat. The coil draws 3.3 W both at closing and holding, so there's no inrush spike to budget for on the DC supply — a steady 3.3 W load from pickup through dropout. Rated for AC-3 duty at 3.5 kW on a 500 V line and 4 kW at 690 V, this contactor handles typical three-phase induction motors in that power band. The AC-4 rating at 400 V is 6.5 A, which covers reversing or plugging applications where the contacts break full-load current more often. For resistive or lightly inductive loads (AC-1), the continuous current rating is 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V — useful for heater banks or transformer primary switching.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. The S00 footprint is 45 mm wide by 60 mm tall by 73 mm deep — a compact slice for a crowded panel. Side-by-side mounting is permitted, so you can gang several contactors without mandatory spacing gaps, though thermal derating still applies in a dense row. Spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded wire, or 2x (24 to 14 AWG). The front face carries an IP20 rating, meaning finger-safe when installed in a closed panel; the terminal blocks themselves are also IP20. Pollution degree 3 classification suits industrial environments with conductive dust or occasional condensation. Operating temperature range is -25 to +60 °C, with a maximum installation altitude of 2 000 m without derating. The 6 mm clearance to adjacent components at the side is the minimum air gap for the rated insulation.