What does the term "double insulation" refer to in electrical equipment?

The term "double insulation" in electrical equipment specifically refers to the implementation of two layers of insulation to protect against electrical shock. This design minimizes the risk of electric shock to users by providing an additional safeguard beyond the basic insulation typically found in electrical devices.

The first layer of insulation is intended to prevent electrical contact with live parts, while the second layer acts as a backup, ensuring that if the first layer fails, there is still a protective barrier. This is particularly important in appliances that are not grounded, as it allows them to be safe for use without the need for a grounding conductor. Such a design eliminates the reliance on grounding to prevent shock, making devices safer and more versatile in various environments.

In contrast, options discussing wire conductors, separate circuits, or limiting current do not relate to the definition of double insulation, as they pertain to different electrical concepts or principles rather than the protective measures provided by insulation in devices.