The Siemens SIRIUS 3RB2065-1GC2 is a solid-state overload relay, not a bimetallic — no thermal fatigue, no ambient tracking drift. It protects motors against phase loss, overload, and asymmetrical load conditions in the main current circuit. Mounts directly on a contactor or as a stand-alone unit on the DIN rail. The main circuit connects via busbar link; auxiliary contacts are screw terminals accepting 0.5–4 mm² solid or 2× 0.5–2.5 mm² stranded.
Auxiliary contact ratings cover the common control voltages you'll find in a panel: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V AC. The 120 V / 4 A rating is the one to size your PLC or relay interface against — it's the highest current point on the curve. The main circuit is rated for AC-3 duty up to 1 000 V, which covers 400 V and 690 V motor feeders without derating. Insulation coordination is Pollution Degree 3 at 1 000 V, so it's safe for ungrounded IT systems and industrial environments with conductive dust. EMC immunity is built in: 2 kV burst on power ports, 1 kV on signal ports (IEC 61000-4-4 severity 3), and 8 kV surge. That's enough for most machine-level panels without external suppression — but if you're on a long cable run near a VFD output, keep the signal wiring separate.
Operates from -25 to +60 °C; stores or ships from -40 to +80 °C. 100 % relative humidity during operation is allowed — condensation is fine as long as it's not actively dripping. Shock rated at 15 g / 11 ms, so it survives forklift drops and machine vibration. Clearances: 0 mm to the sides and top/bottom when mounted on a contactor; 6 mm lateral spacing if stand-alone. Front protection is IP00 — it's intended for enclosed panels, not open washdown zones. Dimensions: 145 mm wide, 147 mm high, 156 mm deep. That depth is the main envelope — check your gland plate clearance if you're retrofitting into a shallow enclosure originally built for a bimetal relay.
ATEX certified for Ex II (2) GD. The PTB 06 ATEX 3001 certificate covers the relay.