You have to be careful (VERY CAREFUL) when looking at minimum distance figures for voltages.
There is the theoretical (breakdown) distance.
There is the minimum distance (worst case) for the environment. Think wind, rain, fog, etc.
There is the minimum distance for materials used. Insulators, enclosures, etc,
There is the minimum distance for jo-public. (..and what they could be [reasonably] expected to be carrying.)
There is the minimum distance for authorised trained workers.
There is the minimum distance for authorised trained workers using equipment near said voltages.
...and many many more.
I regularly measure, calibrate, check, fault find, high voltages (up to 24kV dc) and my high voltage probe (RS Stock No. 360-0300, in calibration with a traceable paper train back to which standard required) is about 10inches from tip to handle, and is rated at 28kV ac rms, BUT there is no way I would use it near OHLE as its intended use takes no account of the environment conditions, the environmental special awareness required and the users (lake of) knowledge of the equipment. It is, however, perfectly safe for the uses I need it for.
Don’t do anything with voltages except what you have been trained to do AND in the environment you are certified to do it in.
DANGER OF DEATH