What this relay is and where it fits
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. Trip class is CLASS 10E, meaning it trips within 10 seconds at 7.2× Ie — fast enough to protect a standard induction motor during a stall or locked-rotor event, but with enough thermal memory to ride through normal starting inrush on a pump or fan. 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.
Electrical ratings — what they mean for your circuit
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.
Environmental and mechanical
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. Mounting position is any — no derating needed for horizontal or inverted orientation. 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.
Compliance and lifecycle
ATEX certified for Ex II (2) GD. The PTB 06 ATEX 3001 certificate covers the relay.