What can be a primary cause of earth leakage in old electrical installations?

The primary cause of earth leakage in old electrical installations is often due to corrosion and wear of insulation. Over time, the insulating materials that protect electrical wires can degrade due to factors like heat, moisture, and aging. When insulation wears down or becomes corroded, it can lead to exposed conductive parts, allowing electric current to leak into the earth. This phenomenon creates safety hazards, as it increases the risk of electric shock and can lead to electrical fires.

In older installations, the materials used for insulation may not meet current safety standards, making them more susceptible to these issues. Therefore, addressing the condition of insulation in older systems is crucial for maintaining safety and preventing leakage issues.