What it is and where it lands
The Siemens 3RT1516-2BB40 is a SIRIUS power contactor in frame size S00, designed for switching loads in control panels and motor circuits. It mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022, so it integrates directly into a DIN-rail enclosure without adapter plates. The 24 VDC coil pulls in at 85 % of rated voltage and holds reliably; the DC switching capacity is 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 numbers that govern whether this contactor handles your DC load without welding contacts. Spring-loaded terminals on the main circuit accept 2x (0.25 to 2.5 mm²) solid or stranded wire, so you land the power wiring without torquing screws — a time-saver on repetitive panel builds.
What the ratings mean for fit
The 45 mm width and 72 mm depth fit a standard 45 mm slot on the DIN rail; height is 60 mm. Side-by-side mounting is permitted, so you can pack multiple contactors in a row without derating for heat buildup at the rated ambient of -25 to +60 °C operating. IP20 on the front and at the terminals means the contactor is finger-safe inside an enclosure but not protected against moisture ingress — it belongs in a panel, not in a washdown zone. Auxiliary contacts rated 9 A per NO or NC. Impulse withstand voltage is 6 kV on both main and auxiliary circuits.