When is insulation most likely to have the lowest resistance?

Insulation is designed to provide a barrier to electrical or thermal conductivity, and its resistance is a critical factor in its effectiveness. When insulation is first placed into service, it is typically at its prime condition. At this stage, it has not yet been subjected to environmental stressors such as moisture, temperature fluctuations, or mechanical wear that can degrade its integrity.

New insulation, when properly installed, has the intended thickness and material characteristics that allow it to offer maximum resistance. The materials used in the insulation are fresh and have not yet been exposed to the factors that can lead to a reduction in their resistance over time.

In contrast, insulation that is old and worn may exhibit lower resistance due to degradation, loss of dielectric strength, or physical damage. Insulation exposed to high temperatures may also suffer a decrease in resistance because thermal exposure can alter the physical structure of the material, making it less effective as an insulator.

Therefore, the point at which insulation is first placed into service represents the moment it has its highest resistance, ensuring it operates efficiently in its intended application.