A double circuit overhead line is a transmission line with two separate, three-phase circuits mounted on a single set of towers. This means instead of three conductors (one for each phase) like a single circuit line, a double circuit line has six conductors (three for each circuit).

This configuration is preferred for several key advantages:

• Increased Capacity and Efficiency: It can transmit roughly double the amount of power for the same right-of-way, making it highly space-efficient for urban or environmentally sensitive areas.

• Enhanced Reliability: Double circuit lines provide redundancy. If one circuit experiences a fault or requires maintenance, the other can remain in service, ensuring a more reliable and uninterrupted power supply.

• Cost Efficiency: While the towers are taller and more robust, sharing the same infrastructure for two circuits is more economical than building two separate single-circuit lines, especially when considering land acquisition and construction costs.