What happens to the "Minimum Approach Distance" at altitudes exceeding 3000 feet?

At altitudes exceeding 3000 feet, the "Minimum Approach Distance" is increased due to the effects of altitude on electrical insulation and the performance of equipment. As altitude increases, the density of the air decreases, resulting in a reduction of the air's insulating properties. This means that electrical arcs can occur over shorter distances compared to at sea level, leading to the necessity for a greater minimum approach distance to ensure safety.

The increased distance is a precautionary measure that allows for a buffer zone to prevent accidental contact with energized parts and to account for the heightened risk of electrical flashover. Therefore, it's essential for linemen and apprentices to recognize that maintaining greater distances at higher altitudes is crucial for their safety and the safety of those working in high-voltage environments.