Siemens 3RU21264CB0 17-22A Thermal Overload Relay

Siemens 3RU21264CB0 17-22A Thermal Overload Relay 

A compact, three-pole thermal overload relay that mounts directly onto Siemens SIRIUS 3RT size S0 contactors. It protects three-phase motors by detecting overcurrent or phase failure and automatically stopping the motor to prevent damage. 

Key Features

• Adjustable current range: 17 to 22 A, suitable for motors up to about 18.5 kW c

• Trip class: Class 10 (trips in ~10 seconds under overload) 

• Reset options: Manual or automatic reset, including TEST and STOP functions and a visible trip indicator

• Connection type: Screw/threaded terminals for both main and auxiliary circuits 

Environment & Physical Specs

• Mounting style: Designed for direct mounting on Siemens 3RT size S0 contactors to save panel space

• Protection rating: IP20 (finger-safe front) 

• Operating temperature: –20 °C to +70 °C (some sources note as low as –40 °C) 

• Contact rating: Up to 22 A at 690 VAC and lower currents at AC/DC voltages for auxiliary contact switching 

• Dimensions & Weight: Approximately 85 × 45 × 85 mm and ~0.42–0.51 lb (0.19–0.23 kg)