The size of a conductor for a 33kV overhead line is determined by three key factors:

• Current-Carrying Capacity (Ampacity): The primary consideration is how much electrical current the conductor needs to carry without overheating. Larger conductors have a greater cross-sectional area, which allows them to carry more current. Overheating can lead to conductor sag and potential damage to the insulation.

• Voltage Drop and Efficiency: A larger conductor has lower electrical resistance. This means less power is lost as heat over long distances, which is crucial for maintaining voltage and efficiency.

• Mechanical Strength: The conductor must have sufficient tensile strength to support its own weight, as well as additional loads from wind and ice. This is particularly important for longer spans. This is why ACSR (Aluminum Conductor Steel Reinforced) conductors, with their steel core, are a popular choice.