Gidday there Jim,
Welcome to ECN, mate!.
I work on Live 11kV-66kV lines as a course of my daily work, as a Line-Mechanic here in New Zealand.
Now, the flash-over distance is a function of the E-M fields that surround a conductor that carries a current, where an earthed (Grounded) part, enters that field.
With 11kV here, we are required to have a clear working distance from bare, live lines of at least one metre (3ft), until such time as the lines are sleeved and covers are in place.
That is working from an IEWP (Insulated Elevated Work Platform).
Full PPE is required even after the gear is in place.
Even then, most of our work is still done via Hot-Sticks.
The further you can keep yourself away from that sort of energy, the better.
It hath no friends once it escapes
Bjarney or Charlie, may be able to prove me wrong.
If they can, please guys, bring it on!.