The Siemens 3RB2016-1RD0 is a SIRIUS solid-state overload relay — a 3-pole device that protects motors against overload and phase loss by monitoring motor current and tripping the contactor when the current exceeds the Class 10E curve. It mounts directly onto a contactor (contactor mounting), so it integrates into a motor starter assembly without extra DIN-rail space.
The auxiliary contact circuit is rated for switching at multiple control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.55 A at 60 V, among others. These are the make/break capacities for the N/O or N/C feedback contacts that signal the PLC or safety circuit. The main terminals are screw-type (accepting 2x 0.25–1.5 mm² solid or 2x 18–14 AWG), while the auxiliary and control circuit uses spring-loaded terminals (2x 0.25–1.5 mm² or 2x 24–16 AWG) — no tool needed for the aux wiring. Surge voltage resistance is rated at 6 kV, and burst immunity meets IEC 61000-4-4 severity 3 (2 kV on power ports, 1 kV on signal ports).
This relay carries ATEX approval PTB 06 ATEX 3001 Ex II (2) GD, meaning it can be used in motor starter circuits that serve equipment in potentially explosive gas or dust atmospheres (Zone 1, 2, 21, 22). It also meets RoHS substance prohibitance as of July 1, 2006. The lifecycle stage is current production.