Siemens Sirius 3RU2126-4BB0 Thermal Overload Relay is a motor-protection device for 3‑phase circuits, adjustable from 14 to 20 A and designed to mount with size S0 contactors. It uses screw-terminals for both the main and auxiliary circuits and supports both manual and automatic reset, with an insulation rating up to 690 V and a surge withstand of 6 kV. The relay is part of the Sirius 3RU2 family, offers Class 10 thermal protection, and is rated for operation from -40 to +70 °C, making it suitable for industrial motor protection applications at typical industrial voltages.
