Which can I use a heat-shrinkable termination for a copper conductor with paper insulation, lead sheath tape armor and PVC jacket ЦСБШнг(А)-LS 3х185-6? Can I insulate somehow one of the four sections of the termination, because my cable has only three wires?
We can recommend the following terminations: 3КВТп-10-150/240(Б) for internal use and 3КНТп-10-150/240(Б) for external use, or 3СТп-10-150/240(Б).
Please pay attention to the fact that terminations 3КВ(Н)Тп-10 and 3СТп-10 are not flame retardant.
Terminations with 4 sections that you mentioned 4ПКТпнг-LS and 4ПСТнг-LS cannot be used for voltage more than 1 kV. Your cable is designed for voltage up to 6 kV, so there is no reason to think about the termination of one section because they cannot be sued with your cable.