The Siemens SIRIUS 3RB2065-2GC2 is a solid-state overload relay with a CLASS 20E trip curve, designed for motor protection in industrial control panels. It can be mounted directly to a contactor or installed standalone, giving flexibility in panel layout. The ATEX Ex II (2) GD certification means it's approved for use in potentially explosive atmospheres — gas and dust — when paired with an appropriate motor and upstream protection.
Key ratings and what they mean for fit
CLASS 20E means the relay allows a 20-second cold-start trip time at 7.2× FLA — typical for medium-inertia loads like conveyors or crushers where a faster CLASS 10 would nuisance-trip on start-up. The operating range spans -25 to +60 °C, with storage and transport down to -40 °C, so it handles unheated warehouses and container shipping. Shock resistance is rated at 15g / 11 ms, enough for mounting on a contactor that sees occasional vibration from switching. The auxiliary contact ratings cover the common control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V — all resistive. For the signal ports, surge immunity is tested to 8 kV and burst to 2 kV on power ports (severity 3 per IEC 61000-4-4), meaning it won't false-trip on a nearby contactor or VFD switching. Pollution degree 3 rated for 1000 V, so it's fit for industrial environments with conductive dust or humidity.
Mounting and wiring
Mounting is contactor-mount or standalone — no DIN rail required, which saves rail space in a dense panel. The main circuit connects via busbar; the control terminals accept solid 0.5…4 mm² or 2× (0.5…2.5 mm²) fine-stranded with ferrules. Dimensions are 145 mm wide, 147 mm high, 156 mm deep — fits a standard 200 mm deep enclosure with room for wiring. Side clearance is 6 mm; zero clearance needed above, below, forward, or backward, so it can be packed tight against other components.