What it is and what it does
The Siemens SIRIUS 3RT1016-1BB42-0AA1 is a size S00 power contactor with a 24 VDC coil, intended for switching motor loads in control panels. It mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, occupying a 45 mm wide footprint. The coil draws 3.3 W during both closing and holding, so the control transformer sizing is straightforward — no inrush spike to oversize for.
Key ratings and what they mean for fit
Rated operational current at AC-12 (resistive load) is 10 A maximum. For motor duty, the contactor is rated 4.5 kW at 500 V and 5.5 kW at 690 V. Under AC-2 duty (slip-ring motors) at 400 V, it handles 4 kW; under AC-4 (plugging/reversing) at 400 V, the rated current is 8.5 A. These are the figures that decide fit for a given motor nameplate — not the AC-12 number. Ambient temperature range is -25 to +60 °C, with pollution degree 3, so it's suited for industrial enclosures without climate control.
Termination and wiring
Main and auxiliary circuits use screw-type terminals. Solid or stranded wire acceptance: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). AWG equivalents: 2x (20 to 16), 2x (18 to 14), 1x 12. The IP20 rating on the front and terminals means it's protected against finger contact but not washdown — standard for panel-mount contactors.
Coordination and protection
For type of coordination 2 (limited damage under short circuit), the required upstream fuse is gL/gG 20 A. For coordination 1 (no damage to the contactor), the fuse is gL/gG 35 A. These are the values to hand to the panel designer for selectivity studies.