Siemens 3RU1126-1FB0 Electrical Overload Relay IP20

Siemens 3RU1126-1FB0 is a SIRIUS thermal overload relay designed for motor protection on three‑phase contactor assemblies, sized S0, with a current release range of 3.5 to 5 A. It includes 1 normally open and 1 normally closed auxiliary contact for control circuits and is intended for mounting on Siemens contactors. Key specs include IP20 protection on the front, insulation voltage up to 690 V, surge voltage resistance of 6 kV, and a typical total power loss of 6 W, with operating temperatures from -20 °C to +70 °C and installation altitude up to 2,000 m. The relay features a 3‑pole main circuit and is classified for 10‑class thermal protection, aligning with its use in 3RT motor protection configurations for reliable, built‑in overload protection.