What this contactor is and where it fits
The Siemens 3RT1015-2KB42 is a SIRIUS power contactor in the Size S00 frame. Its 24 V DC coil draws 2.3 W on both pick-up and hold. The 45 mm wide body snaps onto a 35 mm DIN rail per EN 50022, and the spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded wire, or 2x (24 to 14 AWG). Rated operational current is 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and the contactor handles motor loads up to 3.5 kW at 500 V and 4 kW at 690 V. For AC-4 duty (plugging, inching) at 400 V it's rated 6.5 A. Mechanical endurance is 30 million cycles typical, so it's spec'd for high-cycle applications like conveyor indexing or packaging machinery.
Coordination and surge suppression
Built-in varistor surge suppression across the coil means you don't need an external RC snubber for most PLC or relay driver outputs — the varistor clamps the inductive kick. For fuse coordination, Type 2 (no damage) requires a gL/gG 20 A fuse upstream; Type 1 (short-circuit withstand only) allows a 35 A gL/gG. That's the selectivity call a panel builder needs before laying out the feeder. Degree of pollution 3 means it's rated for conductive pollution environments typical of industrial control panels — no conformal coating needed for normal use. IP20 on the front and terminals keeps fingers out but expects enclosure protection against liquids.
Compliance and documentation
Substance prohibition per RoHS applies from 01 July 2006 — the contactor is RoHS-compliant. The reference code per IEC 81346-2 is Q, which maps to power switching equipment in the standard plant designation system. For a maintenance technician or QA doc controller, the manufacturer provides a declaration of conformity covering the Low Voltage Directive and applicable EN standards; no UL or CSA mark is listed in the evidence, so verify with your local Siemens office if the job requires third-party listing for a specific jurisdiction.