The Siemens 3RF2320-1AA02 is a SIRIUS-brand solid-state contactor, single-phase design, built for zero-point switching of resistive loads. AC-51 rated at 20 A, it handles heating elements, lighting banks, and other non-inductive circuits up to that current. The 22.5 mm width fits standard DIN-rail enclosures; snap-on mounting per IEC 60715 lets it clip alongside other SIRIUS components without extra brackets.
AC-51 is the resistive-load category per IEC 60947-4-3 — the contactor is not rated for motor starting (AC-53) or mixed loads. UL 508 rating is 17.6 A, slightly lower due to UL's different test criteria. The minimum operational current is 500 mA, so it won't reliably switch very small signal loads. I²t maximum of 1,800 A²·s is the let-through energy for fuse coordination — pair with the listed DIAZED (5SB2711) or NEOZED (5SE2320) fuses for short-circuit protection. Control voltage range is 24–230 V AC at 50/60 Hz, or 20–253 V AC across the frequency band. Zero-point switching means the output turns on only near the AC voltage zero crossing — reduces inrush and RFI, but adds a 1 ms ON-delay (plus up to one half-wave). Same delay on turn-off.
Panel integration
Width is 22.5 mm, depth 120 mm, height 95 mm — a compact footprint for a 20 A SSR. Screw-type terminals on both main and control circuits; solid wire 1x (0.5–2.5 mm²) or 2x (0.5–1.0 mm²), stranded 1.5–6 mm². AWG 14–10 for main contacts. Side-by-side mounting is allowed with no derating at 40 °C; above that, follow the derating curve.