The Siemens 3RB2035-2QW1 is a SIRIUS solid-state overload relay. Trip class is CLASS 20E, rated for AC-3 motor switching up to 690 V, and carries ATEX Ex II (2) GD approval. Mounting is stand-alone installation — no DIN rail clip, no snap-on. That means you bolt it directly to a panel backplate or machine frame.
The terminal block accepts solid conductors from 0.5 to 4 mm², or two conductors per clamp (2x 0.5 to 2.5 mm²). For finely stranded wire with ferrules, the range drops to 0.5–2.5 mm² single, 2x 0.5–1.5 mm² double. Environmental tolerance is wide: operate from -25 to +60 °C, store or ship from -40 to +80 °C. Shock rated at 15g for 11 ms — fine for most industrial machinery but not for high-vibration rotating equipment without additional damping. Humidity tolerance is 100% RH, so condensation inside the enclosure won't cause false trips.
The ATEX certificate is PTB 06 ATEX 3001 Ex II (2) GD — that's a Group II device for gas and dust atmospheres, suitable for use with motors in Zone 1/21 and Zone 2/22 areas. EMC immunity includes burst transients at 2 kV on power ports and 1 kV on signal ports, severity level 3 per IEC 61000-4-4, and surge withstand at 6 kV. Pollution degree 3 rated for 690 V — that's the industrial environment with conductive pollution, so no special derating needed in a typical panel.