Line of sight vs. 90degree shortest distance

[CruiserFJ62]

I am working on a project in which I need to know how high voltage arcing occurs. Will arc travel the line of sight path or will it take the shortest distance which has the 90degree angle? What is the reasoning behind the path that it chooses and does anyone have any websites or articles that discusses the arc path? See the attachment for a better idea.

View attachment HV ARCING.doc

 

[Lsos]

My understanding is that it takes the path of least resistance, which is not always either straight, the shortest distance...nor a combination.