- #1

lagrangman

- 13

- 2

I did a little research on this and even if the switching surge factor is 3 and you have a factor of safety of 1.5, in air (3 kV/mm), it corresponds to 1.62 m of maximum arc length, which doesn't explain why towers are so large.

According to "Power System Analysis and Design," by J. Duncan Glover et al., "Line height is selected to satisfy prescribed conductor-to-ground clearances and to control ground-level electric field and its potential shock hazard."

From what I have read the effect of low frequency EMFs on humans is pretty minimal. Has anyone actually been shocked by a power line 10 m away? If so, can someone explain the physics behind this? Does anyone know the calculation the NESC committee uses to come up with minimum clearances?

Thanks a lot.