The Allen-Bradley 140U-J3D3-D10 Molded Case Circuit Breaker (MCCB) comes with a size J frame, 3 poles, and 250 Amps of frame current. It has 400 to 480 Volts AC of rated operational voltage, 100 Amps of current, 50/60 Hertz of frequency, and 35 Kiloamps of interrupting rating. The protection type for the circuit breaker is adjustable magnetic and fixed thermal protection. Its approximate shipping weight is 11.4 pounds. This MCCB provides thermal protection for the control panels as well as branch circuits. Thermal protection can be provided through the use of a bimetallic heater element that is similar to overload relays. Its arc chamber draws the generated arc in contacts within a millisecond during the short circuit while letting the contacts open.

The 140U-J3D3-D10 Molded Case Circuit Breaker is a fundamental component for electrical protection with high-current applications that require an adjustable trip setting. Some of the accessories that are available for this breaker include the multi-tap terminal lugs, rotary operators, under-voltage release, shunt release, NFPA 79 operators, and a padlock for the operators. This 140U-J3D3-D10 Circuit Breaker can be installed as a reverse feed breaker due to the physical equipment arrangement in panel boards. For this application, using thermal-magnetic circuit breakers with the interchangeable trip unit is not possible. If the ambient temperature is above 40 degrees Celsius, the breaker could cause nuisance tripping since the breaker will carry less current compared to its ratings. The 140U-J3D3-D10 Molded Case Circuit Breaker can be used to protect both the plant and operators from the damages resulting from an overcurrent. Its contacts ensure rapid opening under overcurrent conditions.