The Siemens 3RU2116-1KB0 is a SIRIUS thermal overload relay in size S00, designed for motor protection with a CLASS 10 trip characteristic. It mounts directly to a contactor and uses screw-type terminals for the main circuit. Rated for 690 V, it handles 5.5 kW at 400 V and 7.5 kW at 500 V or 690 V. The integrated auxiliary switch provides a tripped message output — useful for signaling a fault condition back to the controller.
Mounting and Integration
Size S00 means a compact footprint: 45 mm wide, 76 mm high, 70 mm deep. It fastens directly to the contactor — no separate DIN-rail bracket needed for the relay itself. Mounting position is any orientation, which simplifies panel layout. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire; use a Pozidriv PZ 2 tip with a 5–6 mm shaft diameter. Temperature compensation is active from -40 to +60 °C, so the trip curve stays accurate across a wide ambient range.
Trip Class and Ratings
CLASS 10 means the relay trips within 10 seconds at a cold start under 7.2× the current setting — standard for standard-duty induction motors that don't need a longer acceleration curve. The rated insulation voltage is 690 V, and the auxiliary contacts handle 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. Per-pole power dissipation is 2.2 W, which matters for thermal buildup in a dense panel. Storage and transport range is -55 to +80 °C; operating range is -40 to +70 °C.