What type of test must insulating gloves undergo in addition to visual inspection?

The correct test that insulating gloves must undergo, in addition to visual inspection, is a dielectric test. This test is critical because it assesses the gloves' ability to withstand electrical potential and identify any breakdown in their insulating properties. Insulating gloves are designed to protect workers from electrical shock, and a dielectric test helps ensure their effectiveness by applying a high-voltage charge to them. If the gloves do not maintain insulation under this test, any defects or damage that may not be visible can be identified, ensuring the safety of the user.

Conducting a visual inspection alone is not sufficient, as small punctures, tears, or inherent weaknesses may not be visible to the naked eye. Thus, the dielectric test is a necessary part of the safety protocol, ensuring that workers are adequately protected when working with electrical systems.