What it is and what it does
The Siemens 3RU2116-0HC1 is a SIRIUS thermal overload relay — size S00, CLASS 10 trip curve — designed to protect three-phase motors against overload and phase failure. It mounts stand-alone in any position and connects via spring-loaded terminals, accepting 2x (0.5... 2.5 mm²) solid or stranded wire. Rated insulation voltage is 690 V, with an operating frequency of 50... 60 Hz. The thermal bimetallic release is temperature-compensated from -40... +60 °C, and the relay operates across -40... +70 °C ambient.
Trip class and what it means for your motor
CLASS 10 means the relay will trip within 10 seconds at 7.2× the full-load current setting — the standard protection for standard induction motors starting under normal load (pumps, fans, compressors). If your application has a longer acceleration time (high-inertia loads like centrifuges or large flywheels), you'd typically step up to CLASS 20 or CLASS 30; this part is not for those.
Auxiliary and tripped indication
An integrated auxiliary switch provides a changeover contact for remote signaling. The relay carries a "Tripped" message indicator — a mechanical flag visible on the front face, so a walk-by check at the panel door tells you the relay has operated without needing a meter.
Mounting and panel fit
Stand-alone installation — no DIN rail required, though it can be mounted on a DIN rail with the appropriate adapter. Dimensions: 102 mm high, 45 mm wide, 79 mm deep. The spring-loaded terminals accept a 3 mm diameter screwdriver shaft (3.0 x 0.5 mm tip) for actuation.
Compliance and documentation
The relay complies with RoHS substance prohibitions effective 10/01/2009. MTTF under high-demand rate is 2,280 years. Storage and transport temperature range: -55... +80 °C.