Theoritically and Practically what could be the maximum value of a High voltage fuse can be constructed?

Thanks & Regards,
Prashant S Akerkar

 

(Making this up as I go along) ...

A fuse knows nothing about voltage ... Just a piece of wire that can handle a specified current ...

With one proviso ... when the fuse blows the space left vacant must not be small enough to allow arcing ... 1mm/1kv approx. in air .

If the wire is blown in a ceramic tube you will have metal vapour , fragments of the wire which will help arcing.

To answer your question I guess an open fuse would be best for very high voltage , one where the wire is exposed to the air , when it melts(blows) the wire falls away , so if the wire is meter long the fuse could deal with about 1MV.... the moment such a fuse blew the metal vapour would cause momentary arcing but it could not be sustained. Once the wire fragments had fallen away and the conductive metal vapour cleared you are left with two terminals separated by a meter of air , effectively an insulator to about 1MV

 

Typically HV fuses are filled with quartz sand in order to quench the arc. The voltage range goes to several Kilovolts.
Max.

 

Theoritically and Practically what could be the maximum value of a High voltage fuse can be constructed?

In theory, you could make a fuse for any desired voltage.

This document lists fuses for up to 36kV.

More info here: https://en.wikipedia.org/wiki/Fuse_(electrical)