What it is and what it does
The Siemens 3RU2116-0GC1 is a SIRIUS thermal overload relay in size S00, designed to protect motors against overload and phase failure by monitoring the motor current and tripping the contactor when the thermal model reaches the trip threshold. The Trip Class 10 rating means it will trip within 10 seconds at 7.2× the set current, which is the standard for standard-duty motor starting applications — fast enough to protect the motor winding but slow enough to ride through the start transient.
Key ratings and what they mean for fit
Rated insulation voltage is 690 V, covering 400 V and 480 V systems with headroom. The auxiliary contact ratings span the control-voltage range you are likely to encounter: 2 A at 24 V, 2 A at 230 V, 1 A at 400 V, and 3 A at 120 V — so it switches PLC inputs or contactor coils across common control voltages without an interposing relay. Motor power assignments: 0.18 kW at 400 V, 0.18 kW at 500 V, 0.25 kW at 690 V. These are the maximum three-phase motor ratings the relay can protect at those line voltages — match these to your motor nameplate, not the contactor rating. The relay is temperature-compensated from -40 °C to +60 °C, so the trip curve stays accurate across the panel ambient range without manual adjustment. Operating ambient is -40 to +70 °C; storage and transport tolerate -55 to +80 °C.
Mounting and wiring
Mounts in any position — stand-alone installation, no DIN-rail adapter required. The spring-loaded terminals on the main circuit accept 2× (0.5 to 2.5 mm²) solid or stranded conductors, so you can loop-through the motor leads without separate terminal blocks. The integrated auxiliary switch (one N/O + one N/C) is wired via the same spring-cage terminals; use a 3 mm diameter screwdriver with a 3.0 × 0.5 mm tip for actuation. Depth is 79 mm, width 45 mm, height 102 mm — the S00 footprint fits alongside S00 contactors in a compact motor-starter row. The 'Tripped' message indicator gives a local visual flag when the relay has operated, which speeds fault-finding on the line.