The Allen-Bradley 140U-H6C3-C60-A Molded Case Circuit Breaker provides two types of protection that include fixed thermal protection and fixed magnetic protection. The Molded Case Circuit Breakers (MCCBs) like this one come in different frame sizes that help to accommodate the needed breaking capacities and current ratings for the applications at hand. The circuit breakers safeguard circuits against ground faults, overloads, and short circuits. The purpose of a circuit breaker is defined and rated differently by different certification organizations. The description given by the National Electrical Manufacturers Association (NEMA) is that a circuit breaker is a device that allows a circuit to open and close automatically, which is decided in advance by the overcurrent rating if the circuit breaker is well applied within its current rating. According to the International Electrotechnical Commission (IEC) Standard 60947-2, a circuit breaker is device with a mechanical switch which can make, break, and carry currents in normal circuit conditions and it can also break currents in conditions where there is specified abnormal circuit situation such as an overload or short circuit situation.

The Allen-Bradley 140U-H6C3-C60-A Molded Case Circuit Breaker has internal modules which include the Auxiliary Contact (AX), Alarm Contact (AL), Auxiliary/Alarm Contact (AX/AL), Shunt Trip (SNT), and Under voltage Release (UVT) modules. The external accessories of the 140U-H6C3-C60-A Circuit Breaker include the Terminal End Cover, DIN Rail Adapter, Thermal Shields, Padlock Kit, Flex-Cable, Phase Barriers, two Rotary mechanisms (variable-depth and direct couple operating mechanism), and the End Cap Kit accessories. Some of the accessories and internal control modules are factory-installed and others are field-installed. Before setting up the 140U-H6C3-C60-A Molded Case Circuit Breaker, carefully read the installation instructions.