What it is and where it lands
The Siemens 3RT1015-1AR01 is a SIRIUS power contactor in the Size S00 frame — the smallest footprint in the family at 45 mm wide, 57.5 mm tall, 72 mm deep. It screws or snaps onto 35 mm DIN rail (EN 50022), so it fits standard panel layouts without special brackets.
What the ratings mean for your load
Rated 4 kW at 690 V AC-3 and 3 kW at 400 V AC-2, so it handles standard three-phase induction motors in that power band — think small pumps, fans, compressors. The AC-4 rating of 6.5 A at 400 V covers reversing or plugging duty where the contacts break full motor current. For resistive loads (AC-12), it carries 10 A. The coil operates on 24 V DC with a 10 A rated value — that's the inrush, not the hold; the actual sealed draw is lower.
Surviving the panel environment
Operating temperature range of -25 to +60 °C means it lives in unventilated enclosures next to warm busbars. Pollution degree 3 — conductive dust and humidity are expected, so the 6 mm side clearance and IP20 finger-safe front matter for creepage and safety. Altitude rated to 2000 m; no derating needed at typical plant elevations.
Terminal wiring and coordination
Screw terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or up to 2x 4 mm². AWG equivalents: 2x (20-16), 2x (18-14), 1x 12. Type 2 coordination calls for a 20 A gL/gG fuse; Type 1 allows 35 A. That's the short-circuit protection you need to specify alongside the contactor — don't let the panel builder guess.