Siemens Overload relay for motor protection, size S0, 27-32AProduct Overview The 3RU2126 4EB0 thermal overload relay is designed for current dependent protection of three phase motors and electrical loads against overload, phase asymmetry, and phase failure. This Size S0, Class 10 relay features an adjustable current range of 27 to 32 A and is optimized for direct mounting on Siemens 3RT2 size 0 contactors (9 to 38 AMPS) to provide reliable motor protection for very high current applications. Key Features