The Siemens 3RB2025-1SB0 is a SIRIUS solid-state overload relay with Class 10E trip curve. It mounts directly onto a contactor (contactor mounting), saving DIN-rail space in the panel and keeping the power loop short.
Trip class CLASS 10E allows a 10-second overload before tripping. The auxiliary contact ratings cover the control circuit: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V — enough to signal a PLC input or drop out a holding contactor.
Mounts on a contactor — clips on without extra brackets. Screw-type terminals on the main circuit accept 0.5 to 4 mm² solid or 2× (0.5 to 2.5 mm²) stranded — standard panel wire sizes, no special ferrules needed. Mounting position is any, which helps when the panel layout is tight and you need to rotate the assembly.
Shock rated at 15g / 11 ms, so it survives panel shipping and vibration on a machine frame. ATEX approval: PTB 06 ATEX 3001 Ex II (2) GD. EMC immunity: 2 kV burst on power ports, 1 kV on signal ports per IEC 61000-4-4 severity level 3 — adequate for industrial environments with contactor switching and drive noise.