Skirts are used to increase tracking distance.
Termination kits typically feature either stress cones or an alternate method to reduce voltage gradient stress at the end of the cable insulation.
Before kits were introduced, stress cones were field fabricated by trained "Cable splicers."
Smaller contractors would have to "Sub out" the termination of medium and higher voltage cables.
The introduction of termination kits allowed industrial electricians to complete the cable terminations.
--------------------
Ohm's law
Not just a good idea;
It's the LAW!