The Siemens 3RB2036-2UB0 is a SIRIUS solid-state overload relay — a CLASS 20E device that protects three-phase motor circuits against overload and phase imbalance by monitoring current and tripping on a delayed curve. It mounts directly onto a contactor (fastening method: contactor mounting), so the relay and contactor form a single compact unit on the DIN rail, saving panel space compared to separate overload blocks.
Three poles for the main current circuit, screw-type terminals accepting solid conductors from 0.5 to 4 mm² (2x 0.5 to 2.5 mm²) and stranded up to 1x 35 mm² or 2x 25 mm². The auxiliary and control circuit also uses screw terminals, accepting 2x 20–14 AWG. Surge voltage resistance is rated at 6 kV, and the relay withstands bursts of 2 kV on power ports and 1 kV on signal ports per IEC 61000-4-4 severity level 3 — meaning it's hardened for industrial electrical noise environments without external filtering. Storage and transport range extends to -40 to +80 °C. Shock resistance is 15g for 11 ms, so it handles the vibration of contactor switching and nearby motor starts without nuisance tripping. Mounting position is any, which helps when panel layout forces a sideways or inverted relay.
Carries ATEX type protection PTB 06 ATEX 3001 Ex II (2) GD, meaning it's approved for use in potentially explosive atmospheres (gas and dust) when installed in the safe area with sensors in the hazardous zone. RoHS compliant with substance prohibition date 07/01/2006.