ABB TF42-20 Thermal Overload Relay, 16-20 A, 690 V AC, Class 10, 3-Pole, 1NO+1NC

With a 6 kV rated impulse withstand voltage and a 690 V AC operational voltage, the ABB TF42-20 thermal overload relay provides robust motor protection in demanding industrial environments. Its 16–20 A setting range and Class 10 tripping ensure fast, reliable response to overloads, while the compact DIN-rail-mountable design simplifies panel integration.

Overview

The TF42-20 is a three-pole thermal overload relay engineered for direct mounting on ABB AF09–AF40 contactors or standalone installation. It offers both manual and automatic reset, temperature compensation from -20 to +60 °C, and screw terminals for secure main and auxiliary connections. Auxiliary contacts include 1 NO and 1 NC, rated for AC-15 and DC-13 duty.

What stands out

• Wide 16–20 A setting range with Class 10 tripping for fast response to overloads.
• Dual reset modes and temperature compensation ensure reliable operation in varying environments.
• Direct mounting on ABB AF series contactors simplifies assembly and reduces wiring.
• IP20 protection and compliance with IEC/EN 60947 standards guarantee safety and interoperability.

Technical details

• Rated operational current: 16–20 A
• Tripping class: 10
• Number of poles: 3
• Rated operational voltage (Ue): 690 V AC
• Rated impulse withstand voltage (Uimp): 6 kV
• Rated insulation voltage (Ui): 690 V
• Auxiliary contacts: 1 NO + 1 NC
• Connection type: screw terminals (main and auxiliary)
• Mounting: direct contactor mounting (AF09–AF40) or standalone
• Reset type: manual and automatic
• Temperature compensation: -20 to +60 °C
• Degree of protection: IP20
• Standards: IEC/EN 60947-1, IEC/EN 60947-4-1, IEC/EN 60947-5-1
• Ambient air temperature for operation: -20 to +60 °C
• Power loss per pole: 0.8 W
• Suitable for contactor series: ABB AF09, AF12, AF16, AF26, AF30, AF38
• Rated operational current AC-15 (auxiliary): 3 A at 230 V AC
• Rated operational current DC-13 (auxiliary): 0.25 A at 125 V DC

Our verdict

The ABB TF42-20 is a dependable choice for motor protection, offering precise overload detection, flexible mounting, and robust electrical ratings in a compact form factor. Its wide temperature compensation and dual reset modes make it suitable for a broad range of industrial applications.