What effect does temperature have on insulation resistance?

• A. Resistance increases with temperature
• B. Resistance decreases with temperature
• C. Temperature has no effect
• D. Resistance is only affected by humidity

Answer: (B)

The correct choice highlights that resistance decreases with an increase in temperature. This relationship is largely due to the properties of the materials used in insulation. As temperature rises, the molecules within the insulating material gain kinetic energy and vibrate more vigorously. This increased movement can lead to a greater number of free charge carriers being available, which ultimately lowers the overall resistance of the insulation.

Furthermore, most insulating materials, like rubber or various plastics, exhibit decreased resistivity when subjected to higher temperatures. Consequently, this can result in a higher likelihood of electrical leakage or failure in insulation systems if they are operated at elevated temperatures for extended periods. Therefore, understanding this relationship is crucial for electrical engineers when designing systems that involve thermal considerations.

In this context, factors like humidity or other environmental variables can influence insulation resistance but are secondary to the more significant effect temperature has. While it's true that humidity can also affect insulation resistance, it does not negate the fundamental principle that temperature plays a more dominant role in determining resistance behavior in electrical insulators.