What it is and what the ratings mean
The Siemens 3RB2065-1MC2 is a SIRIUS solid-state overload relay — the electronic equivalent of a bimetal relay, but with no moving thermal elements to drift or fatigue. Its CLASS 10E trip curve means it will open the motor circuit within 10 seconds at 7.2× the set current, matching the thermal withstand of standard IEC induction motors during a stall or jam. That 0.05 W dissipation per pole (at AC in hot operating state) keeps the panel thermal budget low — relevant when multiple relays are packed on a DIN rail or inside a small enclosure. Rated for contactor mounting or stand-alone installation, it fits directly under a SIRIUS contactor or can be panel-mounted with busbar connections for the main circuit. The IP00 front means it is intended for inside a cabinet — no washdown rating, so keep it behind a gland plate in wet environments.
Where it is used
This overload relay protects three-phase AC motors in industrial automation — conveyors, pumps, fans, compressors — where a solid-state design is preferred over a bimetallic one for accuracy and repeatability. The ATEX Ex II (2) GD certification (PTB 06 ATEX 3001) means it can be installed in the safe area but is approved to protect motors located in Zone 1/21 gas or dust hazardous areas, as long as the associated contactor and wiring meet the installation rules.
Integration notes
Dimensions are 147 mm high, 145 mm wide, 156 mm deep — fits a standard 145 mm-wide DIN-rail footprint. The solid and stranded wire range accepts 0.5 … 4 mm² solid or 0.5 … 2.5 mm² finely stranded with ferrule, with dual-wire capability for daisy-chaining. Mounting position is any orientation; clearance to grounded parts is 0 mm upwards/forwards/backwards/downwards, 6 mm at the side. Ambient operating range is -25 to +60 °C, storage/transport -40 to +80 °C.