What the ratings mean for your panel
The Siemens 3RT6018-1BF41 is a SIRIUS S00-frame power contactor with a 110 V AC coil, sized for motor loads up to 13 kW at 400 V at 60 °C ambient — that's the rating that governs the real-world panel temperature, not the 40 °C figure. The AC-3 switching voltage maxes out at 690 V, so it handles standard 400 V three-phase motors with headroom. The 45 mm width and 73 mm depth mean it fits the standard 35 mm DIN rail footprint per DIN EN 50022, and side-by-side mounting is supported, so you can pack multiple contactors in a row without derating for heat buildup. The operating temperature range of -25 to +60 °C covers most indoor panel environments, and the storage range of -55 to +80 °C means it can sit in an unheated warehouse without issue. The mechanical life of 30 million operations is typical for this class — the electrical life depends on the switching category (AC-1, AC-3, AC-4), so match the duty cycle to your load type.
Mounting and wiring
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 50022. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward, so you can orient it to fit tight enclosures. Main and auxiliary circuits use screw-type terminals; the main terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid or stranded — or 2x 12 AWG for the US market. The auxiliary switch extension is supported if you need feedback contacts.