What is the common reason for the rapid deterioration of rubber insulation?

The correct reason for the rapid deterioration of rubber insulation is related to exposure to ozone. Rubber insulation, especially in electrical applications, is susceptible to environmental factors that can cause it to break down. Ozone, which is a strong oxidizing agent, can cause cracking and aging of rubber materials. This degradation occurs because ozone reacts with the double bonds present in the rubber polymer, leading to a loss of elasticity and structural integrity over time.

While exposure to heat, oil, and sunlight can also negatively affect rubber insulation, ozone is particularly damaging as it specifically alters the molecular structure of rubber. Heat can accelerate other forms of degradation, oil can cause swelling and softening, and sunlight can lead to surface hardening and fading, but ozone is uniquely harmful because it directly affects the material's chemical bonds, leading to rapid deterioration. Hence, the significant concern with rubber insulation in electrical applications is its vulnerability to ozone in particular.