The Omron G3NA-420B-UTU DC5-24 is a solid-state relay from the G3NA series, switching AC loads up to 20 A at 200 to 480 VAC. The input side accepts 5 to 24 VDC, making it compatible with standard PLC or controller outputs. Switching is zero-cross phototriac, so it turns on near the AC zero voltage — reduces inrush and EMI on resistive or lightly inductive loads.
Surface-mount style with screw terminals; no DIN-rail clip on this variant. The relay is finger-safe (touch-safe terminals per the listing). No heat sink included — the 20 A rating is the maximum output current both with and without a heat sink, meaning the relay is rated to carry 20 A in free air at its listed temperature range (-22 to 176 °F). In a warm panel or at continuous full load, a heat sink is still advisable for thermal margin; the datasheet's derating curve will tell you if your ambient requires one.
Insulation resistance is 100 megaohm. The LED indicator gives a quick visual on coil power.