There are three critical measurements that are essential for the safe and reliable operation of any overhead line:

• Sag: This is the vertical distance between the highest point of a conductor and its lowest point in a span. Proper sag ensures the conductor has enough slack to handle temperature changes, wind, and ice loads without becoming too taut. Inaccurate sag can lead to conductor failure or insufficient clearance.

• Tension: This is the mechanical force exerted on the conductor. It's directly related to sag and must be within the conductor's design limits. Excess tension can cause stress on the conductor and supporting structures, leading to a system failure. Conversely, too little tension can result in excessive sag, which can create dangerous clearance issues.

• Clearance: This is the minimum required distance between the energized conductor and the ground, buildings, roads, or other objects. Maintaining proper clearance is a fundamental safety requirement mandated by regulations to prevent electrical shock, fires, and other hazards.