What is an electric circuit that is no longer in use and completely isolated called?

An electric circuit that is no longer in use and completely isolated is referred to as an abandoned circuit. This term signifies that the circuit has been deliberately taken out of service and should be treated as if it has no active function or potential risk. Abandoned circuits require special attention to ensure they are properly decommissioned and marked, to prevent any accidental reconnection or safety hazards.

The concept of an abandoned circuit is particularly important in mining or industrial settings where improperly managed circuits can lead to dangerous conditions. Workers must be aware of such circuits to avoid contact or confusion with active systems.

While "disconnected circuit," "inactive circuit," and "open circuit" might sound similar, they do not carry the same implications of complete isolation and disuse that the term "abandoned circuit" does. A disconnected circuit implies that it has been physically disconnected but may still have potential for reconnection, while an inactive circuit may suggest it's not actively in use but can be restored to functionality. An open circuit generally denotes a break in the circuit path, preventing current from flowing, but it does not necessarily mean the circuit has been permanently taken out of service.