600v Wire tension

[living2learn]

I have a switchgear lineup on a concrete pad that is on piers, and runs 100' to the building with 4 sets of 500 kcmil. The switchgear is moving. How could I determine how much it can move before something dramatic happens?

100' seems like it could take some movement

 

[PHovnanian]

It depends on how tightly it is strung to begin with. You should make a measurement of the sag from end to end (the elevation of both end points and the lowest point in the span). You could probably plug that into some line design software that allows you to adjust the end point horizontal distance and see how that affects the conductor tension.

This can be compared to the maximum allowable tension for the given wire type or support messenger. In addition, you can add snow/ice loading and wind loading (if applicable).

 

[LiteYear]

If the movement is not very slow, remember to consider harmonics - you could easily have a dramatic situation on your hands if the movement happened to excite a standing wave in the cable.