2. Design differences between overhead and underground systems

The purpose of this section is to explain how overhead and underground networks differ in terms of design and operation, and why the transition from one to the other cannot be made without an overall analysis.

These considerations only apply to MV, as LV overhead (mostly twisted) and underground networks in France have the same tree-like structure. On the other hand, the sophistication required for underground connections and their accessories makes LV networks more expensive.