The Allen-Bradley 140G-J2F3-C90 circuit breaker is a molded case circuit breaker with a 25 kiloAmps breaking capacity at 480 Volts AC. It uses adjustable thermal and adjustable magnetic trip units. However, although the unit is adjustable, it can only be adjusted between 1250 Amps and 2500 Amps. The trip unit, in addition to providing protection against short circuits, also provides protection against long-term current overloads that exist for longer than approximately 10 seconds. Since the response of the bimetal used in the thermal unit of 140G-J2F3-C90 circuit breaker unit relies on current and time, the 140G-J2F3-C90 circuit breaker is capable of providing a long-time delay for light overloads and a speedy response for heavy overloads.

The 140G-J2F3-C90 circuit breaker should be mounted and operated in environments with an ambient temperature not exceeding the recommended rating of 40 degrees Celsius in order to avoid device damage and the malfunctioning of the thermal trip unit. The National Electrical Code (NEC) specifies that a long-time delay of the thermal element is capable of initiating a circuit-clearing operation when the current reaches 125% of the rated conductor or equipment ampacity. The 140G-J2F3-C90 circuit breaker has a J Frame. Breakers with this frame type have a frame current rating of 250 Amps. Although the trip unit is adjustable to up to 2500 Amps, the current must not exceed the frame rating. The 140G-J2F3-C90 circuit breaker is CE-marked, CSA-certified, and UL-listed. The 140G-J2F3-C90 circuit breaker is part of the Allen-Bradley 140G family of molded case circuit breakers. Breakers in this family comply with standards such as the IEC 60947-2, UL 489, and the CSA 22.2, No.5 standards.