The Siemens SIRIUS 3RB2025-2RB0 is a solid-state overload relay with a CLASS 20E trip characteristic, designed for contactor mounting in motor feeder circuits. It carries ATEX certification PTB 06 ATEX 3001 Ex II (2) GD, meaning it is approved for use in potentially explosive atmospheres as an associated apparatus — the relay itself can be mounted outside the hazardous area while protecting motors inside Zone 1 or 2 (gas) and Zone 21 or 22 (dust). This makes it a compliance-ready choice for chemical, pharmaceutical, or grain-handling lines where the protection device must not become an ignition source.
Key ratings and what they mean for your panel
The CLASS 20E trip class means the relay allows a locked-rotor current duration of up to 20 seconds at ambient temperature before tripping — sized for standard induction motors with moderate starting inertia (conveyors, fans, pumps). This is not a fast-trip class; if your application has a high-inertia load requiring longer acceleration, you would need a CLASS 30 or field-adjustable relay. Mounting is contactor-mount, meaning it clips directly onto the output side of a matching SIRIUS contactor, saving DIN-rail space. The 45 mm width and 73 mm height mean it occupies the same footprint as the contactor it pairs with, so panel layout stays predictable. Side clearance to adjacent devices is 6 mm, which is standard for this class — no special spacing required. The screw-type terminals for the main current circuit accept solid conductors from 0.5 to 4 mm², or two conductors 2x (0.5 to 2.5 mm²). AWG equivalents are 2x (14 to 10). This is a standard range for motor circuits up to the relay's rated insulation voltage of 690 V at AC-3. The IP20 front protection means it is touch-safe but not washdown-rated — keep it inside the enclosure. Operating temperature range is -25 to +60 °C, with storage and transport tolerance from -40 to +80 °C. It withstands shock at 15g for 11 ms and can be mounted in any position. Surge voltage resistance is rated at 6 kV, and EMC burst immunity meets IEC 61000-4-4 severity level 3: 2 kV on power ports, 1 kV on signal ports. These ratings confirm it is suitable for industrial control panels in standard factory environments without additional suppression.
Compliance documentation
The relay carries ATEX certification PTB 06 ATEX 3001 Ex II (2) GD, which is a European explosive-atmosphere directive. It is also designed to meet IEC 61000-4-4 EMC immunity at severity level 3. For RoHS, REACH, and UL documentation, the manufacturer provides a declaration of conformity and the ATEX certificate as part of the standard documentation pack — these are available at the time of order. The reference code per DIN EN 81346-2 is F, for circuit protection functions.