The Siemens 3RU1126-1JB0-ZW97 is a SIRIUS thermal overload relay in Size S0, Trip Class 10, designed for motor protection in control panels. It mounts directly onto a contactor — no separate DIN-rail footprint needed — and uses screw-type terminals for both main and auxiliary circuits. Trip Class 10 means it will trip within 10 seconds at 7.2× the full-load current setting, which is the standard for standard-duty induction motor starts — pumps, fans, compressors. The S0 frame size mates with Siemens 3RT2 contactors in the same size class.
Mounting & Clearance
Fastened by contactor mounting — clips onto the contactor body, no extra panel space. Clearance requirements: 0 mm upwards, 0 mm forwards, 0 mm backwards, 0 mm downwards, 6 mm at the side. The mounting position allows ±135° rotation on a vertical surface and ±45° tilt front-to-back. IP20 on the front means finger-safe touch protection; the enclosure itself is not sealed against moisture, so keep it inside a panel rated for the environment.
Wire Terminations
Main circuit terminals accept solid or finely stranded wire with core-end processing: 2x (0.5... 1.5 mm²) and 2x (0.75... 2.5 mm²). Auxiliary/control circuit terminals use the same screw-type and wire ranges. AWG equivalents: 2x (20... 16) and 2x (18... 14).
Environmental & Compliance
Operating temperature range -20 to +70 °C, storage and transport -55 to +80 °C. Relative humidity up to 100% during operation. Shock resistance 8g / 10 ms. Surge voltage resistance rated at 6 kV. Reference code per IEC 81346-2 is F.
Auxiliary Contact Ratings
Auxiliary contact ratings per pole: 2.2 W thermal dissipation. Switching capacities: 1 A at 24 V, 0.22 A at 110 V, 3 A at 120 V, 0.22 A at 125 V, 0.11 A at 220 V, 2 A at 230 V, 1 A at 400 V. These are the make/break ratings for the built-in auxiliary contacts.