What it is and what it does
The Siemens 3RU2116-0DJ0 is a SIRIUS thermal overload relay, size S00, designed to protect motors against overload and phase failure. It mounts directly onto a contactor — no separate base needed — and uses a bimetallic thermal release that tracks motor heating. Trip Class 10 means it will trip within 10 seconds at 7.2× the set current, which is the standard for standard-duty motor starting (pumps, fans, compressors) where the start is under a few seconds.
Key ratings and what they mean for fit
Rated insulation voltage is 690 V, and the AC-3e rated maximum voltage matches at 690 V — so it's good for 400 V and 480 V systems with headroom. The auxiliary contacts are integrated, not a bolt-on add-on: at 24 V they switch 2 A, at 120 V they switch 3 A, and at 230 V they switch 2 A. That covers most PLC input and contactor coil circuits. At 690 V the auxiliary contacts still handle 0.75 A, enough for signaling on higher-voltage control schemes. Power dissipation per pole is 1.6 W — three poles total 4.8 W at full load. In a crowded S00 panel that heat adds up, so leave breathing space around the relay. The integrated auxiliary switch means no separate block to buy and wire, which saves a DIN-rail slot and a wiring step. Operating temperature range is -40 to +70 °C, with temperature compensation active from -40 to +60 °C. Storage and transport range is -55 to +80 °C. That covers most indoor and outdoor cabinet conditions — no derating needed for a typical 40 °C panel ambient.
Mounting and wiring
Fastening method is contactor mounting — it snaps directly onto the matching SIRIUS contactor, no screws or DIN-rail clip required. Mounting position is any orientation, which helps when the panel layout is tight. Main current circuit connection uses ring cable lugs, and the main contact screws are M3. The screwdriver spec is Pozidriv PZ2 with a shaft diameter of 5 to 6 mm. Dimensions: 76 mm high, 45 mm wide, 70 mm deep. That's the standard S00 footprint — fits the same panel cutout as the contactor it mounts on.