The 140U-H6S3-D12 isolator is a molded case isolator that has been designed to provide current protection to motors and conduits, including different groups of industrial equipment. It has been introduced by Allen-Bradley in the 140U product line of circuit protection equipment. This specific isolator model is a molded case switch that works as an isolator devices. The Allen-Bradley 140U-H6S3-D12 molded case isolator (also known as a disconnector), is commonly used to isolate transformers from service during the maintenance operations or whenever isolation is required. It is often used in applications in substations. Even though isolator devices are designed to stop the current offload conditions, they can also operate on different load conditions.

The Allen-Bradley 140U-H6S3-D12 molded case isolator has a current rating of 125 Amps and it belongs to the Frame H product line. It also has an interrupting capacity of 60 to 69 kA. These specifications need to match the equipment specifications so that the isolator can operate safely. Unlike other circuit isolators, the Allen-Bradley 140U-H6S3-D12 molded case isolator is operated manually. This isolator is an electronic device and it can cut off the operations of just a portion of a substation system instead of the whole system when a fault occurs. This isolator can operate at 40 degrees Celsius maximum without any kind of derating. It can also be used at a temperature of up to 70 degrees Celsius when it is derated accordingly. It is important to note that any kind of wiring that is used with protective equipment needs to be appropriate for operations at temperatures of up to 75 degrees Celsius so that they will be resistant to the heat that is produced by current flow.