The 140U-JD3D3-D22 circuit breaker is a compact molded case circuit breaker which belongs to Allen-Bradley’s Bulletin 140U series. The continuous current rating for the 140U-JD3D3-D22 circuit breaker is 225 Amps. The enclosure of the circuit breaker has a JD-type frame. The 140U-JD3D3-D22 circuit breaker comes with an integrated fixed thermal–adjustable magnetic trip module. The 140U-JD3D3-D22 circuit breaker can be used wherever the protection of main circuits and branch circuits against ground faults, short circuits, or overloads is required. The 140U-JD3D3-D22 circuit breaker is well suited to installation inside industrial switchboards, panelboards, and individual enclosures. The number of poles on the 140U-JD3D3-D22 circuit breaker is three. The interrupting capacity rating for the 140U-JD3D3-D22 circuit breaker ranges from a minimum of 30 kiloamps to a maximum of 39 kiloamps.

The minimum and maximum continuous operating current ratings for the 140U series breakers are 15 Amps and 1200 Amps, respectively. Breakers can be ordered with either electronic or thermal-magnetic trip modules. Electronic trip modules offer advanced protection through the adjustable long time, adjustable short time, adjustable instantaneous trip, and adjustable ground fault settings. Common combinations for the electronic trip settings include LS, LSI, LSG, and LSIG. Allen-Bradley recommends several guidelines related to the installation and maintenance of high voltage/high current devices such as the 140U-JD3D3-D22 circuit breaker. The primary precaution that needs to be taken is the main electrical power disconnection. This will ensure the safety of the technicians who are carrying out breaker installation and servicing and will also protect associated electrical equipment against damage. Furthermore only technical personnel who possess the necessary relevant training and experience should be involved in the installation or maintenance of the 140U-JD3D3-D22 circuit breaker. Personnel working on electrical systems should have all the necessary tools and equipment that are recommended for protection against electrical shock.