Questions on Sag And Tension

1. Sag and Tension Questions
1. Calculate the sag for a span of 200m if the ultimate tensile strength of conductor is 5758kgf. The
weight of conductor is 604 kgf/km. allow a factor of safety of 2. [1.048m]
2. A transmission line has a span of 275m between level supports. The conductor has a diameter of
19.53mm, weighs 0.844kgf/m and has an ultimate breaking strength of 7950kgf. Each conductor
has a radial covering of ice 9.53mm thick and is subjected to a horizontal wind pressure of
40kgf/m2 of the ice covered projected area. If the factor of safety is 2, calculate the deflected
sag and the vertical component of the sag. One cubic meter of ice weighs 913.5kgf.
[5.36m, 3.9m]
3. An overhead transmission line has a span of 240m between level supports. Calculate the
maximum sag if the conductor weighs 727 kgf/km and has a breaking strength of 6880 kgf.
Allow a factor of safety of 2. Neglect wind and ice loading. [1.52m]
4. A transmission line has a span of 180m between level supports. The conductor has a cross-
sectional area of 129m2, weighs 1.17kgf/m and has a breaking stress of 42kgf/mm2. Calculate
the sag for a safety of 5, allowing for a maximum wind pressure of 125kgf/m2 of projected
surface. [7.41m]
5. Calculate the sag in an overhead conductor under the following conditions: length of span,
150m, cross-sectional area of conductor 125mm2, breaking strength 42kgf/mm2, factor of safety
5, weight of conductor 0.859kgf/m, maximum wind pressure, 150kgf/mm2. [5.56m]
6. The line conductor of a transmission line has an overall diameter of 19.53mm, weighs 0.844kgf/
m, and an ultimate breaking strength of 7950kgf. If the factor of safety is to be 2 when the
conductor has an ice load of 1 kgf/m and a horizontal wind pressure of 1.5kgf/m, find
approximately the vertical sag which corresponds to this loading for a 300m span between level
supports. [5.52m]