The Siemens 3RU7126-1CB0 is a SIRIUS thermal overload relay in the S0 frame size, rated for a 2.5 A operational current and a Class 10 trip characteristic. It mounts directly to a S0 contactor (e.g., the 3RT10 series) via the contactor-mounting fastening method, forming a compact motor starter package for a DIN-rail panel.
The relay accepts a wide mounting position range: vertical surface with ±135° rotation and ±45° tilt forward/backward, giving panel builders flexibility in tight enclosures. Side spacing to grounded parts must be at least 6 mm. Terminals are screw-type on both the main and auxiliary circuits. Main circuit terminals accept 2×(0.5…1.5 mm²) or 2×(0.75…2.5 mm²) solid/stranded, torqued to 2…2.5 N·m. Auxiliary terminals take the same wire sizes at 0.8…1.2 N·m.
Ratings & Environment
Rated operational current is 2.5 A AC/DC for the main circuit at up to 690 V, 50/60 Hz. Auxiliary contacts are rated 3 A at 24 V and 2 A at 230 V, with a DC-13 rating of 1 A at 24 V for the control circuit. Installation altitude is limited to 2000 m above sea level. The relay withstands 6 kV surge voltage and 8g/11 ms shock per IEC 60068-2-27.