All electrical tape, of whatever form, pretty much has to pass the same tests. The only real variable is the voltage rating - and that's based upon only a two-layer thickness.
"Ordinary" electrical tape is listed for 600v. So are the usual splicing tapes and putties. The 'self fusing' nature of the splicing tapes does make the final set waterproof, and the thickness is a real help to building up thickness.
There are reasons for building up some thickness, apart from electrical insulation. For example, to cover sharp edges.
