When can metallic parts of electrical tools become energized?

Metallic parts of electrical tools can become energized primarily when there is a break in the insulation of wiring. Insulation is essential for preventing electrical current from touching conductive parts that are not meant to conduct electricity. If the insulation is compromised due to wear, damage, or environmental factors, it can create a path for electrical current to flow to the metallic parts of the tool. This situation presents a significant shock hazard to users, as they may inadvertently touch these energized parts.

The other options do not lead to the metallic parts becoming energized. Keeping tools dry, for instance, actually helps prevent moisture-related issues, like corrosion or accidental grounding, which can lead to unsafe electrical conditions. Grounding is a safety measure designed to prevent electrical shock and only works effectively when properly established; if done right, it would ensure that any stray current is directed safely to the ground rather than through the user. Similarly, when electrical tools are inactive and turned off, they are not energized, indicating that there is no current flow, making the metallic parts safe to touch under normal conditions, provided there are no underlying issues with the tool's insulation.