I would like to offer a different take on this, for readers in countries which follow IEC derived wiring regulations as opposed to US/Canadian NEC (most places other than North America). https://en.wikipedia.org/wiki/Electrical_code

Electrical insulation tape is actually an oxymoron. It generally does not have an insulation rating in V, kV, etc, therefore it cannot be guaranteed to provide insulation for a given voltage (other than maybe for extra low voltage systems <55VAC/120VDC). Also PVC has a relatively low melting point of 60 deg C and the tape is quite thin so liable to mechanical damage. Over time the adhesive gets sticky, migrates and loses adhesion, so there's no guarantee it wont slowly peel off. How many turns are required to limit the risk from the above factors?? this is never specified.

There is a key difference between countries with follow NEC where wire nuts are allowed and those using IEC derived wiring regulations. in IEC countries, wires are fixed in screw/sprung terminals and are always terminated so there is no bare conductor exposed so there should be no need to use insulation tape in formal electrical engineering if best practise is followed.

For identification of cables coloured sleeves and alphanumeric markers are available.

For insulation in proximity to high temperature lamps and heating elements woven fibre glass can be used.

For application such as covering soldered joints in electronics work, a better solution is to use sleeving such as heat shrink sleeving.

For protection outdoors denzo tape or similar can be used.

I would like to offer a different take on this, in particular aimed at readers in countries which follow IEC derived wiring regulations (most places other than North America) as opposed to US/Canadian National Elctrical Code (NEC) https://en.wikipedia.org/wiki/Electrical_code

Electrical insulation tape is actually an oxymoron. It generally does not have an insulation rating in V, kV, etc, therefore it cannot be guaranteed to provide insulation for any given voltage (other than maybe for extra low voltage systems <55VAC/120VDC). Also PVC has a relatively low melting point of 60 deg C and the tape is quite thin so liable to mechanical damage. Over time the adhesive gets sticky, migrates and loses adhesion, so there's no guarantee it wont slowly peel off. How many turns are required to limit the risk from the above factors?? This is never specified.

There is a key difference between countries with follow NEC where wire nuts are allowed and those using IEC derived wiring regulations where they are not. In IEC countries, flexible conductorswires are usually fixed in screw/sprung terminals (or occasionally crimp terminals) and are always terminated so the insulation is covered by the terminal/connector shroud so there is no bare conductor exposed. All new electrical panels and enclosure use IP21 'touch proof' terminals and connectors. Therefore there should be no need to use insulation tape in formal electrical engineering if best practise is followed.

For identification of cables coloured sleeves and alphanumeric markers are available.

For insulation in proximity to high temperature lamps and heating elements woven fibre glass can be used.

For application such as covering soldered joints in electronics work, a better solution is to use sleeving such as heat shrink sleeving.

For protection outdoors denzo tape or similar can be used.