The Siemens 3RU5136-4BB0 is a SIRIUS thermal overload relay for motor protection, adjustable from 14 to 20 A with a Trip Class 10 characteristic. It mounts directly onto a matching S2-size contactor, saving panel space and eliminating separate wiring between the relay and contactor.
The adjustable current range of 14 to 20 A sets the overload pickup point — set it to the motor's full-load amps. The rated operational current is 20 A at 690 V, 50/60 Hz, so it covers 400 V and 480 V motor circuits common in European and North American panels.
Fastening is contactor mounting — clips onto the S2-size contactor, no DIN rail or extra brackets. Mounting position allows ±135° rotation and ±45° tilt from vertical, so it fits angled backplanes. Side spacing to grounded parts is 6 mm. Dimensions: 55 mm wide, 105 mm high, 118 mm deep — fits standard panel cutouts. Main circuit terminals are screw-type, top and bottom, accepting 2×(0.5–1.5 mm²) or 2×(0.75–2.5 mm²) solid/stranded, or AWG 18–3. Auxiliary terminals also screw-type, accepting 2×(20–16) or 2×(18–14) AWG. Tightening torque for main contacts: 3–5 N·m.