The Siemens SIRIUS 3RU2116-1KJ0 is a thermal overload relay in the S00 frame size, designed for direct mounting onto a contactor. It protects motors against overload and phase failure with a Class 10 trip characteristic, meaning it will trip within 10 seconds at 7.2× the set current — standard for general-purpose induction motor starting where the load doesn't require a longer acceleration ramp.
Ratings and what they mean for fit
Rated insulation voltage is 690 V, matching the maximum AC-3e operating voltage of 690 V. That covers 400 V, 480 V, 600 V, and 690 V line supplies common in European and North American industrial panels. The motor power assignments at those voltages are 5.5 kW at 400 V, 7.5 kW at 500 V, and 7.5 kW at 690 V — so it's sized for a 5.5–7.5 kW motor range depending on your line voltage. The integrated auxiliary switch (1 N/O + 1 N/C) is rated for switching at various control voltages: 2 A at 24 V and 230 V, 3 A at 120 V, 1 A at 400 V, and 0.75 A at 690 V. These are the contact ratings for the trip-indication circuit — the "Tripped" message contact that signals the PLC or annunciator when the relay has operated. At 24 VDC control common in modern panels, you get 2 A switching capacity, enough for a typical PLC input or contactor coil. Power dissipation per pole is 2.2 W, so three poles total 6.6 W under load. That's modest — no special ventilation required in a standard IP20 enclosure, but worth noting if you're packing multiple relays in a small cabinet.
Mounting and integration
Fastening method is contactor mounting — it snaps directly onto the matching S00 contactor (e.g., 3RT1016 series). No DIN rail required for the relay itself; it rides on the contactor. Mounting position is any orientation, which simplifies panel layout. Dimensions: 45 mm wide, 76 mm high, 70 mm deep — the width matches a standard S00 contactor footprint, so it doesn't add lateral space. Main circuit connection is via ring cable lug (M3 screw), suitable for the current range of an S00 relay. The auxiliary circuit uses screw terminals with a Pozidriv PZ2 tip, 5–6 mm shaft diameter. Temperature compensation is active from -40 °C to +60 °C, so the trip curve stays accurate across the operating range without manual adjustment.
Environmental and compliance
Operating temperature range is -40 to +70 °C; storage and transport range is -55 to +80 °C. The relay carries a substance prohibition date of 10/01/2009, indicating RoHS compliance from that date forward. MTTF at high demand rate is 2,280 years — a reliability figure that supports safety-related applications where the relay is part of a monitored circuit.