The Allen-Bradley 140U-Q6D3-D50 circuit breaker is a Q-frame circuit breaker with three poles. It is part of the Allen-Bradley Bulletin 140U product line which also includes molded case switches. The continuous current rating of the 140U-Q6D3-D50 circuit breaker is 500 Amps. A fixed thermal–adjustable magnetic trip module comes with the breaker and the thermal trip rating is fixed at 500 Amps. Other breaker specifications include 65 kiloamps of breaking capacity at 480 Volts AC and 70 kiloamps of breaking capacity at 400 Volts AC. The service breaking capacity at a line frequency of 50 Hertz is 100 kiloamps at 220 Volts AC, 70 kiloamps at 380 Volts AC, 38 kiloamps at 500 Volts AC, and 13 kiloamps at 690 Volts AC.

Several internal control accessories are available which can be installed on the 140U-Q6D3-D50 circuit breaker in the field. These include a shunt trip that provides remote breaker tripping and the undervoltage release which allows for automatic breaker tripping. Both the shunt trip and the undervoltage release cannot be installed on the same circuit breaker. An alarm contact and an auxiliary contact are also available. The alarm contact gives an indication when the circuit breaker is tripped and the auxiliary contact indicates when the breaker is “on” or “of” electrically. External accessories available for the 140U-Q6D3-D50 circuit breaker from Allen-Bradley include a padlock kit, terminal lugs, phase barriers, and flex-cable operating mechanism. Allen-Bradley 140U series circuit breakers can be used to protect against overvoltage and short circuits. They can be used as main circuit protection devices and branch circuit protection devices. The dimensions of the 140U-Q6D3-D50 circuit breaker are 317.5 x 209.55 x 111.12 millimeters.