Panel fit and wiring
The 3RT2018-2LF42-0LA0 is a Siemens SIRIUS power contactor in the S00 frame — the smallest in the family, at 45 mm wide and 121 mm deep. It snaps onto 35 mm DIN rail per EN 60715 and can be screw-mounted if the panel spec calls for it. The 110 V DC coil uses spring-type terminals, so no screwdriver needed for the magnet wire — just strip and push. Main contact wiring accepts solid conductors from 0.5 mm² up to 4 mm², which covers most control circuit runs in a standard panel.
What the ratings mean for your load
The DC coil pulls in at 110 V nominal, with a pickup threshold of 0.7 × rated value — so it'll hold in down to about 77 V. Dropout time is 7 to 20 ms on DC, arcing time 10 to 15 ms. That's fast enough for most motor start/stop circuits but not for safety-rated instant-off; if you need that, pair it with a separate safety relay. For motor loads, the contactor carries 14 A at 480 V — that's a 7.5 hp motor at 480 V three-phase, typical for a small conveyor or pump. At 24 V DC on the auxiliary side, it switches 10 A, which covers most PLC output cards and indicator loads.
Clearance and mounting position
Mounting position is flexible: ±180° rotation on a vertical surface, and you can tilt it forward or backward by ±22.5°. That helps when you're squeezing it into a tight gland plate area. Minimum clearances: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm to the side. The 121 mm depth is the body only — add another 10–15 mm for wiring clearance in front of the terminals. Storage temp range is -55 to +80 °C, operating -40 to +70 °C, so it'll sit fine in an unheated warehouse or a hot panel near a motor.