The Siemens 3RF3320-2DA04 is a 1-pole solid-state contactor from the SIRIUS 3RF33 family, rated for AC-1 resistive loads at 20 A and 40 °C ambient. The 48-460 V operating range covers common European and North American line voltages, and the 24 V DC control input integrates directly with PLC or safety-relay outputs. Spring-loaded terminals speed panel wiring and hold up under vibration.
What the AC-1 rating means for your load
The AC-1 rating of 20 A at 40 °C applies to resistive or slightly inductive loads — heaters, incandescent lamps, or resistive furnace elements. For motor or transformer loads (AC-3 or AC-4 duty), the contactor must be derated; the datasheet's AC-51 through AC-55b curves define the actual switching capacity. The 1-pole configuration switches one line; for two- or three-phase resistive loads, use two or three units ganged.
The 105 x 27 x 122 mm package snaps onto a 35 mm DIN rail per EN 60715. Spring-loaded terminals accept 0.5–6 mm² conductors; strip length is 10 mm.