Where are overhead secondary mains typically installed?

Overhead secondary mains are typically installed on vertical racks. This type of installation allows for efficient use of space and facilitates ease of access and maintenance. Vertical racks are particularly useful in urban environments where overhead lines are subject to space constraints, as they can be positioned to maximize clearance and minimize disruption to the surrounding area.

Installing overhead secondary mains on vertical racks also enhances their visibility and safety, as it keeps them elevated from ground-level activities. This positioning helps to reduce the likelihood of accidental damage from vehicles or pedestrians.

In contrast, other options do not provide the same advantages as vertical rack installations. Horizontal racks may not offer the same level of clearance and could interfere with other infrastructures. Underground installations, while preventing surface obstruction, do not fit the definition of "overhead" mains. Flat surfaces also do not provide the necessary elevation for overhead lines, thus highlighting the practicality of vertical racks for this specific application.