What are high-voltage lines characterized by?

High-voltage lines are characterized by voltages that exceed 750 V. This categorization is significant because it reflects the operational standards and safety protocols associated with distributing electricity over long distances and through various infrastructures. In electrical engineering, high-voltage transmission is essential for efficient power delivery, as higher voltages allow for reduced current, which minimizes energy loss due to heat generated in the conductors.

The other responses describe different ranges of voltage classifications or contexts that do not represent high-voltage lines. Choices that indicate less than 100 V or specify voltages below the high-voltage threshold do not align with the standards used in the industry. Furthermore, referencing electrical wires solely used in homes does not pertain to the classification of high-voltage lines since residential wiring typically encountered operates at much lower voltages. Thus, the definition that encompasses voltages greater than 750 V clearly identifies what constitutes high-voltage lines effectively.