What it is and what it does
The Siemens 3RU2116-0JC0 is a SIRIUS-brand thermal overload relay, size S00, designed for motor protection in control panels. It mounts directly onto a contactor (fastening method: contactor mounting) and provides Class 10 trip protection — meaning it will trip within 10 seconds at 7.2× the thermal setting current, standard for protecting standard induction motors during start-up.
Key ratings and what they mean for fit
Rated voltage is 690 V, covering 400 V and 480 V line-to-line systems common in industrial distribution. The AC-3e rated maximum voltage is also 690 V, so it switches motor loads at those voltages without derating. The relay carries a power rating of 0.25 kW at 400 V, 0.37 kW at 500 V, and 0.55 kW at 690 V — these are the motor sizes it protects at those supply voltages. Auxiliary contact ratings are given for several control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V, which tells you what the signal contacts can handle when feeding a PLC input or a contactor coil. The S00 frame size (45 mm wide, 87 mm high, 70 mm deep) is the smallest in the SIRIUS overload relay family, designed to pair with S00 contactors in compact motor starter assemblies. The 70 mm depth is important for panel layout — it fits standard 60 mm deep enclosures with clearance for wiring. Spring-loaded terminals accept 2 × (0.5 to 2.5 mm²) solid or stranded wire, so no lug crimping needed for the main circuit. Operating temperature range is -40 to +70 °C, with temperature compensation active from -40 to +60 °C — meaning the thermal curve stays accurate even in cold storage areas or hot machine cabinets. Storage and transport range extends to -55 to +80 °C. The auxiliary switch is integrated, so no separate add-on block is required for the trip/alarm signal.
Where it goes and how it mounts
Mounts directly onto a SIRIUS S00 contactor — no DIN rail adapter needed, though the contactor itself clips onto the rail. Any mounting position is allowed, so vertical or horizontal panel layouts both work. The screwdriver slot for the terminal screws accepts a 3 mm diameter shaft with a 3.0 × 0.5 mm tip — standard electrician's screwdriver. The relay operates at 50/60 Hz, matching line frequency globally.