Siemens 3RU2126-4CC0 Overload Relay Thermal Motor Protection

Siemens 3RU2126-4CC0 is a thermal overload relay for motor protection in Siemens Sirius 3RU2 contactor systems. It covers a 17 to 22 A motor current range, is built in the S0 frame size, and provides IEC Class 10 thermal protection. Designed for contactor mounting, the unit attaches to the main circuit side of a Siemens contactor and uses spring-type terminals for both the main circuit and the auxiliary circuit, with a reset that can be performed manually or automatically. The 3RU2 family is intended for inverse-time delayed protection of loads with normal starting characteristics, guarding motors against overheating due to overload or phase faults. Typical applications include protection of three-phase motors in industrial drives—pumps, fans, conveyors, and processing equipment—where reliable, resettable protection is required in control panels.