The Siemens SIRIUS 3RT1015-2MB41-0KT0 is a size S00 power contactor with a 24 V DC coil, rated for switching motor loads up to 4 kW at 690 V AC (AC-3) or 3 kW at 400 V AC (AC-2). The spring-loaded main terminals accept 2x (0.25 to 2.5 mm²) solid or stranded wire, or 2x (24 to 14 AWG).
The AC-3 rating (3.5 kW at 500 V, 4 kW at 690 V) covers standard squirrel-cage motor starting — the contactor makes and breaks the motor under full load. The AC-12 rating (10 A maximum) covers resistive loads like heaters. For DC switching, the contactor is rated 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — these are resistive DC ratings. DC arcs are harder to extinguish than AC, so the current drops sharply as voltage rises. If you're switching DC motor or solenoid loads, derate further per the manufacturer's DC-13 curve. Short-circuit protection: with type 2 coordination (no welding of contacts), use a gL/gG fuse rated 20 A. With type 1 coordination (welding allowed but no fire risk), a 35 A gL/gG fuse is permitted.
IP20 on the front and at the terminals — finger-safe but not washdown-rated. The contactor is intended for enclosed control panels, not open or wet environments. The spring-loaded terminals reduce wiring time: strip 8 mm, insert, release. No screwdriver needed for the main circuit.