The Siemens 3RT1015-2AN21 is a SIRIUS power contactor in the compact S00 frame size — 45 mm wide, 60 mm tall, 73 mm deep — designed for switching motor loads and resistive circuits in control panels. The 24 VDC coil is the key selection anchor here. Auxiliary contact ratings are 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — these are the limits for signal-level switching, not the main poles. For motor duty, the AC-2 rating at 400 V is 3 kW, and the AC-4 rating at 400 V is 6.5 A; that tells you this contactor handles reversing or inching duty cycles, not just across-the-line starts. Spring-loaded terminals on the main circuit accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). That means no screwdriver torque check on the power connections — strip, insert, done. The front and terminal areas carry IP20 finger protection, standard for enclosed panel use.
Coordination and environment
This is the number your panel designer needs for the short-circuit protection scheme — don't guess it from the motor FLA. That covers most industrial environments but not clean-room or medical front-end applications without additional enclosure derating. Side-by-side mounting is permitted, which is expected for the S00 frame — you can pack these at 45 mm pitch without derating, as long as ambient stays within the -25 to +60 °C window.