What it is and what it does
The Siemens 3RU1116-1BB0-ZW96 is a SIRIUS Size S00 thermal overload relay — a 3-pole device that protects motor circuits against sustained overcurrent by mimicking the motor's thermal response. It mounts directly onto a contactor, so the power circuit passes through the relay's bimetal strips before reaching the motor. When the heat buildup exceeds the Class 10 trip curve, the relay opens its NC contact in the control loop, dropping out the contactor coil.
What the ratings mean for fit
Class 10 trip means the relay will open within 10 seconds at 7.2× the current setting — standard for standard-duty induction motors that don't need a long start delay. The Size S00 frame limits the continuous current range this relay can handle; it's the smallest SIRIUS overload relay footprint, sized for contactors up to around 12 A rated operational current in AC-3 duty. The screw-type terminals on both main and auxiliary circuits accept 2x (0.5...1.5 mm²) solid or 2x (0.75...2.5 mm²) stranded, with AWG equivalents of 2x (20...16) and 2x (18...14). That's enough for the motor leads and control wiring on a small pump or fan.
Where it goes and how it mounts
This relay is designed for contactor mounting — it snaps onto the bottom of a SIRIUS S00 contactor, forming a compact motor starter package on a DIN rail. The mounting position is flexible: vertical surface with ±135° rotation and ±45° tilt front-to-back. Clearance requirements are tight: 0 mm upwards, forwards, backwards, and downwards, with only 6 mm needed at the side. That means it packs into a small enclosure without breathing room. The IP20 front protection is standard for a panel-mounted device — no washdown rating, so keep it inside the cabinet.
Compliance and approvals
The relay carries ATEX approval DMT 98 ATEX G 001 for use in potentially explosive gas atmospheres. It also meets RoHS substance prohibitance dated July 1, 2006. The reference code per IEC 81346-2 is F (protective device). Surge voltage resistance is rated at 6 kV, and the relay withstands 8g shock for 10 ms — enough for industrial panel vibration. Operating temperature range is -20 to +70 °C, with storage and transport from -55 to +80 °C.