What information is essential for reading a sag chart?

The correct answer is based on the importance of understanding how wire characteristics and environmental factors affect the sag in a power line. The sag chart is a tool used to determine the amount of sag (the droop) that a wire will have under various conditions.

Wire type is crucial because different types of wire (such as aluminum or copper) have different physical properties, such as tensile strength and expansion characteristics. The size of the wire is equally important; thicker wires generally sag less than thinner wires due to their structural integrity and weight distribution. Lastly, temperature directly impacts the material properties of the wire. As temperature increases, most wires expand, resulting in increased sag.

Having the right combination of wire type, size, and temperature allows linemen to accurately predict sag under specific conditions, ensuring safety and compliance with electrical regulations. This knowledge is vital for performing effective line installations and maintenance.