The Allen-Bradley 140U-Q6D3-D35 circuit breaker is an assembled circuit breaker where the trip module comes preinstalled on the breaker. The product line to which the 140U-Q6D3-D35 circuit breaker belongs is the Bulletin 140U product line. The trip module is a thermal-magnetic module. The thermal trip is set at 350 Amps and the magnetic trip setting can be set according to the customer requirements by means of adjustment to the buttons provided on the breaker poles. A screwdriver can aid in setting the desired magnetic trip positions. The trip modules are calibrated at 40 degrees Celsius and 50 to 60 Hertz. The performance of the trip module can vary at other frequencies and ambient conditions.

The rated current of the 140U-Q6D3-D35 circuit breaker is 350 Amps. The ultimate breaking capacity ratings for the 140U-Q6D3-D35 circuit breaker are 25 kiloamps at 690 Volts AC line voltage, 50 kiloamps at 500 Volts AC line voltage, 70 kiloamps at 380 Volts AC line voltage, and 100 kiloamps at 240 Volts AC line voltage. Allen-Bradley recommends avoiding equipment maintenance while the equipment is energized because death, serious injury, and property damage can occur due to contact with the energized high power electrical equipment. The technicians working on the electrical systems should verify that all voltages are absent before starting maintenance activities. All precautions which are recognized as industry standards should always be followed. While working on the 140U-Q6D3- D35 circuit breaker, care should be taken to avoid applying excessive torque to the screws because it may lead to shearing on the screws.