The 140U-J3X3 circuit breaker is a three-phase circuit breaker enclosed inside a molded case. The current rating of the breaker is 250 Amps and it comes in a J frame. It can interrupt a circuit at 40/35 kA. The input voltage range of the breaker ranges between 380 and 480 Volts AC. However, the breaker can work well with both AC and DC power supplies. It can also work with single-phase applications. The operating frequency of the breaker is 50/60 Hertz which depends on the amount of load in the system. The trip unit of the breaker is fixed in this circuit breaker variant with support for both thermal and magnetic trips. It provides overload and short circuit protection and it meets different standards, including the CE, KEMA, and CSA standards. The 140U-J3X3 circuit breaker dissipates 20 Watts of energy as heat. The internal components of the breaker are manufactured using high-quality materials, which results in optimal performance in different load conditions.

The Allen-Bradley 140U-J3X3 circuit breaker is very easy to install and replace. The breaker comes with variable rotary depth operating mechanisms and it supports different interrupting ratings. The maximum temperature should not exceed 60 degrees Celsius. The breaker is cooled by using the convection cooling method. Proper airflow should be maintained between the breaker and the nearest ventilation source for a stable operating temperature. The 140U-J3X3 circuit breaker is equipped with a power lever to switch the breaker on and off. A red push-to-trip button is also present which can be used to check whether the breaker is working properly or not.