Conductor sag is the vertical distance between the lowest point of a conductor span and the imaginary horizontal line connecting its two support points (towers). Accurate measurement and adjustment of sag during stringing are absolutely crucial because:

• Safety Clearances: Correct sag ensures the conductor maintains safe vertical clearance from the ground, buildings, roads, and other lines, preventing hazards.

• Structural Integrity: Sag directly influences the tension in the conductor. Too much sag means low tension and potential for excessive swing, while too little sag means excessively high tension, which can overstress towers, insulators, and the conductor itself, leading to premature failure.

• Electrical Performance: Incorrect sag can affect line impedance and overall power transmission efficiency.

• Longevity: Properly sagged conductors experience optimal mechanical stress, contributing to a longer service life. Stringing crews utilize sag charts, tension meters, and sometimes optical or laser sighting tools to achieve the exact sag required by the engineering design for various temperature conditions.