What it is and what it does
The Siemens 3RU1116-1HC1 is a SIRIUS thermal overload relay in the Size S00 frame, designed to protect three-phase motor circuits against overload and phase failure. It is a bimetallic, ambient-compensated relay with a Trip Class 10 characteristic, meaning it will trip within 10 seconds at 7.2× the set current — standard for general-purpose motor starting where the load accelerates quickly (pumps, fans, compressors). The relay mounts directly to a SIRIUS contactor or stands alone via its fastening method for stand-alone installation.
Key ratings and what they mean for fit
The 3RU1116-1HC1 is a 3-pole relay with Cage Clamp terminals on both the main current circuit and the auxiliary/control circuit. The main circuit terminals accept 2x (0.5... 2.5 mm²) solid or 2x (24... 14) AWG; the auxiliary circuit accepts 2x (0.5... 1.5 mm²) finely stranded with core end processing or 2x (20... 14) AWG. This terminal style gives a vibration-resistant, maintenance-free connection — no screw retorquing needed during commissioning. The auxiliary contact ratings are specified by control voltage: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. These are the thermal continuous current ratings for the N/O and N/C contacts — useful when sizing the control transformer or verifying the PLC input card can sink the contact current. Power dissipation per pole is 2.2 W, totaling 6.6 W for the three poles at rated current. This matters for enclosure thermal calculations — in a sealed panel with multiple relays, the cumulative heat can raise internal ambient above the relay's -20... +70 °C operating range.
Where it goes and how it mounts
The relay occupies a 45 mm width on the DIN rail, with a depth of 78 mm and height of 92 mm. Mounting position allows a vertical mounting surface with +/-135° rotation and +/-45° tilt front-to-back — flexible for tight cabinets. Clearance requirements: 0 mm upwards, forwards, backwards, and downwards; 6 mm at the side. This zero-clearance design lets you pack relays side-by-side without derating for air circulation, though the cumulative heat from each pole's 2.2 W still needs to be managed. Front protection is IP20 — finger-safe but not sealed. The relay is intended for installation inside a control cabinet with a higher enclosure rating; it is not rated for washdown or outdoor exposure.
Approvals and compliance
The 3RU1116-1HC1 carries ATEX approval (DMT 98 ATEX G 001) for use in potentially explosive atmospheres — the relay can be installed in Zone 2 or Zone 22 areas when paired with an appropriate contactor and housed in a certified enclosure. Surge voltage resistance is rated at 6 kV, and the reference code per IEC 81346-2 is F (protective device). The substance prohibition date of 01.07.2006 aligns with RoHS compliance. Relative humidity during operation is rated for 100 % — condensing conditions are acceptable within the temperature range.