What it is and what it does
The Siemens 3RT1015-1AH02 is a SIRIUS power contactor in size S00, designed for switching motor loads and resistive circuits in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 50022, using either screw or snap-on fixing. The 24 VDC coil draws its rated holding current through the integrated suppression; verify free-wheel diode polarity before energizing inductive loads downstream. Rated at 10 A at 24 V for DC switching, and 3.5 kW at 500 V or 4 kW at 690 V for AC motor duty. The AC-4 rating at 400 V is 6.5 A, which governs the switching of inching or reversing loads — the contactor's real-world limit for frequent plugging or jogging. For standard AC-3 motor starting, the 3 kW at 400 V (AC-2) is the load it handles in a pump or fan application. Mechanical life is 30 million cycles typical, so it outlasts most panel refreshes in continuous-duty applications like conveyors or compressors. The operating temperature range of -25 to +60 °C covers unheated plant floors and enclosed cabinets.
Mounting and wiring
Width is 45 mm, height 57.5 mm, depth 72 mm — the S00 footprint fits a standard 45 mm DIN-rail pitch. Side-by-side mounting is permitted with zero gap, so you can pack contactors tight on the rail. The front face is IP20, terminals are IP20; the enclosure is suitable for open panel mounting with no additional finger protection cover needed. Main circuit terminals accept solid or stranded wire: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²). AWG equivalents are 2x (20 to 16), 2x (18 to 14), or 1x 12. Screw terminals require a PZ1 or similar bit; strip length follows the terminal marking. Pollution degree 3 means it tolerates conductive dust in industrial environments without conformal coating. Side clearance of 6 mm is required on the front for ventilation; no side gap needed between units. Maximum operating altitude is 2 000 m without derating.
Protection coordination
For Type 2 coordination (no damage to the contactor under short circuit), use a gL/gG fuse rated 20 A. For Type 1 coordination (contactor may need replacement after fault), the fuse can be 35 A. These are the Siemens-recommended values for the main circuit; verify with the specific motor data for exact sizing.