What the 20 A AC-1 rating means for your panel
The 3RF3320-1AA04 is a single-pole solid-state contactor from the Siemens SIRIUS 3RF33 series, rated 20 A in AC-1 duty at 40 °C ambient. AC-1 is the resistive load category (IEC 60947-4-2) — heaters, incandescent lighting, or resistive banks where inrush is near steady-state. That 20 A figure is the continuous current it can carry without derating; for motor or transformer loads (AC-3/AC-4), the switching current limit will be lower, so size this into a resistive circuit, not a motor starter. The switching range is 48–460 VAC on the power side, with a 24 VDC coil. That DC coil draw is low — a standard 24 VDC PLC output or control relay can drive it without an interposing relay, simplifying the control loop. Screw terminals keep wiring straightforward for panel builders; no special crimp tooling needed.
RoHS compliant since 15 Jan 2024. No UL or CSA mark is listed in the base spec, but the SIRIUS 3RF33 family typically carries CE and UKCA for European and UK markets; verify specific project approval requirements against the full manufacturer declaration.