The Siemens SIRIUS 3RU2126-1HB0 thermal overload relay delivers dependable motor protection for compact starters and industrial control panels. Engineered for direct coupling with SIRIUS contactors, it safeguards three-phase motors against overload and phase asymmetry while minimizing installation space and ensuring consistent, long-term performance.

Built on proven bimetal technology with Class 10 tripping, the 3RU2126-1HB0 supports precise, adjustable current matching for coordinated protection with upstream devices. A clearly accessible reset and test function, finger-safe screw terminals, and direct-on-contactor mounting streamline commissioning and service. Integrated auxiliary contacts (1 NO/1 NC) provide reliable status signaling to PLCs and interlocks, and compliance with IEC/EN 60947-4-1 enables use across a wide range of industrial and building applications.

Whether you are configuring new motor starters or standardizing critical spares for maintenance, this relay helps reduce downtime and protect assets throughout the equipment lifecycle, backed by a 1-year warranty to provide added assurance in demanding environments.

• Brand: Siemens
• Series: SIRIUS 3RU21
• Model: 3RU2126-1HB0
• Product type: Thermal overload relay, Class 10
• Auxiliary contacts: 1 NO + 1 NC
• Connection type: Screw terminals
• Mounting: Direct-on contactor or DIN rail (with adapter)
• Standards: IEC/EN 60947-4-1