Siemens SIRIUS 3RU2116-1BB0 Thermal Overload Relay, 1.1-1.6 A, Class 10, Screw Terminals

In a busy motor control center, a technician needs a reliable way to protect a small three-phase motor from overloads and phase failures. The Siemens 3RU2116-1BB0 thermal overload relay steps in: set its dial to the motor's full load current between 1.1 and 1.6 A, mount it directly on a contactor or as a standalone unit, and it will trip within seconds if the current creeps too high. Its compact S00 size fits tight panels, while the manual/automatic reset and test function make commissioning straightforward.

Key specifications

• Current setting range: 1.1 – 1.6 A
• Size S00, suitable for contactor mounting or standalone installation
• 3-pole main circuit with screw-type terminals
• Auxiliary contacts: 1 NO + 1 NC
• Overload release class: CLASS 10
• Phase failure sensitivity: Yes
• Reset function: manual / automatic
• Rated insulation voltage (Ui): 690 V
• Rated operational voltage (Ue): 690 V AC
• Rated impulse withstand voltage (Uimp): 6 kV
• Degree of protection: IP20
• Ambient operating temperature: -20 to +60 °C
• Main circuit conductor cross-section: 0.5 – 4 mm² (solid/stranded)
• Auxiliary circuit conductor cross-section: 0.5 – 2.5 mm² (solid/stranded)
• Test function: Yes
• Suitable motor power at 400 V AC: 0.37 kW

Why choose it

This relay is part of the proven SIRIUS 3RU2 series, known for dependable thermal protection in industrial environments. Its phase failure sensitivity guards against single-phasing, a common cause of motor burnout. The screw terminals accept a wide range of conductor sizes, and the compact S00 footprint saves space without sacrificing performance. With both manual and automatic reset options, you can tailor the response to your application.

Ideal use cases

• Protecting small three-phase motors in conveyors, pumps, fans, and machine tools
• Retrofitting existing motor starters where a compact thermal relay is needed
• Applications requiring phase failure detection and Class 10 tripping characteristics
• Panels with limited space where S00 size is essential

Good to know

The relay is designed for use with Siemens SIRIUS contactors of size S00, but it can also be mounted standalone using appropriate accessories. The test function allows you to simulate an overload and verify the tripping mechanism without applying actual load current. Always ensure the current setting matches the motor's full load current to avoid nuisance tripping or insufficient protection.