What is a common sign of moisture affecting electrical insulation?

Moisture affecting electrical insulation often leads to a significant decrease in insulation resistance. When insulation materials absorb moisture, their ability to resist the flow of electrical current diminishes, creating pathways for leakage currents. This reduction in insulation resistance can ultimately lead to short circuits or equipment failure, making it a critical indicator of moisture problems in electrical systems.

In contrast, while increased conductivity might suggest easier movement of electrical current due to moisture, it is not the most direct sign of moisture damage to insulation itself. Flaking paint, although it could indicate moisture issues, is more associated with structural problems and not specifically tied to electrical insulation. A corrosive odor may suggest chemical reactions due to moisture but lacks the specific linkage to the electrical properties of insulation like decreasing insulation resistance does. Thus, reduced insulation resistance is a primary and definitive sign of moisture affecting the integrity of electrical insulation.