3RU2126-4EB0

The 3RU2126-4EB0 is a thermal overload relay from Siemens' SIRIUS 3RU2 series, Size S0, designed to mount directly onto a compatible Size 0 SIRIUS contactor to provide motor overload and phase-failure protection as part of a complete starter combination. Adjustable from , it lets you dial in the relay's trip point to match your motor's full-load current, protecting against sustained overload conditions and phase asymmetry or failure. It's a key companion component when pairing with a magnetic-only motor circuit protector to build a complete, code-compliant motor starter for larger motor loads within the Size S0 range. Electrically, the 3RU2126-4EB0 uses a bi-metal thermal sensing mechanism with Class 10 tripping characteristics, appropriate for standard motor starting duty. It includes one normally open and one normally closed auxiliary contact for signaling a fault condition to a control circuit or PLC, along with a manual or automatic reset option after a trip. Ambient-temperature compensation helps the relay maintain accurate tripping across a range of installation environments. Mechanically, the 3RU2126-4EB0 mounts directly to a compatible Size 0 SIRIUS contactor, keeping the starter combination compact without separate wiring between the contactor and overload relay. It uses screw-type terminals for both the main and auxiliary circuits, and its accessories are designed to fit consistently across the broader SIRIUS product range. This makes the 3RU2126-4EB0 a practical, cost-effective choice for building or maintaining motor starter combinations at this size class. Purchase the 3RU2126-4EB0 at Electrical.com, your reliable partner for industrial and commercial electrical products. Our selection includes trusted motor control products and relays from manufacturers like Siemens, Eaton, Cutler-Hammer, and Schneider Electric, backed by a knowledgeable sales team ready to assist with technical questions, product selection, and support.