SIRIUS S00 power contactor — 24 VDC coil, 10 A AC-12
The Siemens 3RT1016-1AR21 is a SIRIUS S00 power contactor with a 24 VDC coil, rated for 10 A in AC-12 duty (resistive loads at 50/60 Hz). It snaps onto 35 mm DIN rail per EN 50022 and uses screw-type terminals for the main circuit. The AC-12 rating of 10 A at 24 V tells you this contactor is sized for switching resistive loads like heaters or lighting banks in control panels — not motor starting. For motor duty, check the AC-2 and AC-4 ratings: 4 kW at 400 V in AC-2 (slip-ring motors) and 8.5 A at 400 V in AC-4 (plugging/inching). Coil draws from a 24 VDC supply; the contactor holds in down to roughly 18 V before dropout. The S00 frame keeps the footprint compact at 45 mm wide, 57.5 mm tall, and 72 mm deep — fits tight DIN-rail rows.
Mounting and integration
Mounts via screw or snap-on onto 35 mm standard rail per DIN EN 50022. Side-by-side mounting is permitted with 6 mm clearance at the side for heat dissipation. Pollution degree 3 rating means it's suited for industrial environments with conductive pollution — typical for control cabinets near machinery. Terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid/stranded. AWG equivalents: 2x (20 to 16), 2x (18 to 14), 1x 12. Front and terminal protection is IP20 — finger-safe for panel installation, not for washdown. Operating temperature range is -25 to +60 °C during operation. Maximum operating altitude is 2,000 m without derating.
Short-circuit coordination and protection
For Type 2 coordination (no damage to contactor after fault), use gL/gG fuses rated 20 A. For Type 1 coordination (contactor may need replacement after fault), the fuse rating goes up to 35 A gL/gG. This matters when specifying upstream protection for the panel.