What this part is and where it fits
The Siemens 3RU1116-1AB0-ZX95 is a SIRIUS Size S00 thermal overload relay, designed for motor protection in control panels. It mounts directly onto a contactor via the fastening method, saving DIN-rail space and simplifying the wiring between the relay and the contactor's main circuit. The relay is rated CLASS 10 trip class, meaning it will trip within 10 seconds at a locked-rotor current of 7.2× the thermal setting — a standard choice for protecting standard induction motors during startup. Its IP20 front protection means the front face is finger-safe against accidental contact, which is typical for enclosed panel installations where the relay is not in a washdown zone.
Mounting and integration notes
The relay occupies 45 mm width, 87 mm height, and 78 mm depth. It mounts on a vertical surface with ±135° rotation and ±45° tilt forward/backward, giving flexibility for panel layouts where the contactor is not perfectly upright. Clearance requirements: 0 mm upwards, forwards, backwards, and downwards; 6 mm at the side. This tight clearance allows dense packing on the DIN rail or contactor assembly. Main and auxiliary circuits use screw-type terminals. The main circuit accepts 2× (0.5…1.5 mm²) or 2× (0.75…2.5 mm²) solid or finely stranded wire with ferrule; auxiliary contacts accept 2× (20…16) or 2× (18…14) AWG. Strip length and torque values follow the terminal marking on the relay body.
Electrical ratings and what they mean for the buyer
The auxiliary contact ratings cover common control voltages: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. These are the maximum continuous currents the auxiliary contacts can switch at those voltages — useful for confirming the relay can drive the PLC input or contactor coil in the circuit. Power dissipation per pole is 1.9 W, so total heat for the three-pole relay is 5.7 W. This matters for panel thermal calculations when multiple relays are ganged together. Surge voltage resistance is rated at 6 kV, which means the relay can withstand transient overvoltages common in industrial power networks without insulation breakdown. Operating temperature range is -20 to +70 °C; storage and transport range is -55 to +80 °C. The relay is rated for 100 % relative humidity during operation, so it handles condensation-prone environments inside non-sealed enclosures. Shock resistance is 8 g for 10 ms, sufficient for mounting on contactors that see vibration from switching or nearby motor starters.