What it is and what it does
The Siemens 3RT2018-2BB41-0CC0 is a SIRIUS power contactor in the compact S00 frame size, designed for switching motor loads and resistive loads in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 60715 via screw and snap-on fastening, and its 45 mm width fits standard panel layouts. The coil is rated 24 VDC, and the main contacts are rated for switching at various DC voltage levels: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. This means the contactor can handle DC loads across a range of control voltages, but the current capability drops significantly as voltage rises — a key consideration for DC load switching where arc extinction is harder than AC. Switching frequency varies by duty class: up to 1,000 operations per hour at AC-1 (resistive loads), 750 ops/h at AC-2 and AC-3 (motor starting/running), and 250 ops/h at AC-4 (plugging/inching). The AC-3e rating also allows 750 ops/h. These limits govern how aggressively you can cycle the contactor in a given application — exceeding them shortens mechanical life.
Mounting and integration
The contactor accepts solid or stranded conductors from 0.5 to 4 mm², including dual conductors of the same range. Spring-type terminals on the magnet coil mean no screw torqueing — strip, insert, done. That saves time on a panel build and avoids loose-terminal callbacks. Clearance requirements: 10 mm upwards and forwards, 10 mm downwards, and 6 mm at the side. The mounting position allows +/-180° rotation on a vertical surface and can be tilted forward/backward by +/-22.5°. This flexibility helps when fitting into tight or oddly oriented enclosures. Dimensions are 70 mm high, 45 mm wide, and 73 mm deep — the depth is the key number for gland-plate clearance in shallow enclosures. The S00 frame is the smallest SIRIUS contactor footprint, so it leaves room for auxiliary contact blocks or overload relays alongside.
Environmental and lifecycle
Operating temperature range is -25 to +60 °C, storage range -55 to +80 °C. The storage range is wider — that covers shipping and warehouse conditions, not running duty. For a solar farm or desert installation, the 60 °C operating ceiling is adequate but leaves no headroom for internal cabinet heating above ambient; derate if the panel runs hot.