Which statement correctly describes a double-insulated power tool?

A double-insulated power tool is designed with two layers of insulation to protect the user from electric shock, thus making it safe to use without an external grounding conductor. This type of tool eliminates the need for grounding by ensuring that even if a fault occurs, the user is still protected. The double insulation method not only provides safety in normal operating conditions but also allows for flexibility in various environments where grounding is not feasible.

The other options highlight important safety considerations but don’t accurately describe the characteristics of a double-insulated power tool. While it's true that a double-insulated tool typically should not be used in wet conditions, this does not define its design or purpose. The indication that it requires additional grounding is contrary to its very function of eliminating the need for grounding. Furthermore, saying it is designed for high-voltage applications is misleading, as double insulation is more about protection in general usage rather than being specific to high-voltage scenarios.