ABB TF42-4.2 Thermal Overload Relay, 3.4-4.2 A, Class 10, 3-Pole, 690 V AC, Screw Terminals

In industrial motor control panels, protecting three-phase motors from sustained overcurrent is critical. The ABB TF42-4.2 thermal overload relay is built for this task, offering reliable protection for motors with a rated operational current range of 3.4 to 4.2 A. It is commonly paired with ABB AF series contactors such as AF09 through AF38, providing a compact and dependable solution for machine builders and panel shops.

Key specifications

• Rated operational current range: 3.4 - 4.2 A
• Tripping class: Class 10
• Number of poles: 3
• Rated operational voltage (Ue): 690 V AC
• Rated insulation voltage (Ui): 690 V
• Rated impulse withstand voltage (Uimp): 6 kV
• Auxiliary contacts: 1 NO + 1 NC
• Mounting type: Direct mounting to contactor / Stand-alone
• Reset type: Manual and Automatic
• Ambient operating temperature: -25 to +60 °C
• Ambient storage temperature: -50 to +80 °C
• Degree of protection: IP20
• Terminal type: Screw terminals
• Standards: IEC/EN 60947-4-1, IEC/EN 60947-5-1
• Overload protection type: Thermal

Why choose it

The TF42-4.2 delivers precise thermal overload protection with a Class 10 tripping characteristic, ensuring motors are disconnected quickly under overload conditions. Its dual reset modes (manual and automatic) offer flexibility for different operational requirements. The relay's wide ambient temperature range and robust design make it suitable for demanding industrial environments, while direct mounting to ABB contactors simplifies installation and reduces wiring time.

Ideal use cases

• Protecting three-phase motors in conveyor systems, pumps, fans, and compressors
• Machine tools and packaging machinery requiring reliable motor protection
• HVAC equipment and industrial automation panels
• Applications where direct mounting to ABB AF series contactors is preferred

Good to know

The TF42-4.2 is a thermal overload relay with a current setting range of 3.4 to 4.2 A. It features screw terminals for secure connections and provides one normally open and one normally closed auxiliary contact for control and signaling. The relay complies with international standards IEC/EN 60947-4-1 and IEC/EN 60947-5-1, ensuring safety and performance. Its IP20 protection rating means it is intended for installation inside an enclosure. For stand-alone use, a suitable mounting adapter may be required.