Are thermal insulators good electrical insulators?

noA2: Not necessarily. Solid plastics or solid glass or ceramic have high dielectric strength but not good thermal insulation. Closed-cell foam has good thermal insulating properties but not as good...

Usually. A2: Not, not usually. Something with high thermal efficiency usually has "pockets" of gas in it, say, closed-cell polyurethane foam. The total dielectric strength, therefore, is not much...

yes i thinkA2: No, Not in Solid form. It is a Very Good insulator If sprayed into closed-cell foam or spun into fabric.

Plastics are a good electrical insulators because they are insulators. Electricity could not pass through them unlike copper. Another good example of insulators is rubber.

yes copper is actually a very good insulator to both heat and electric conducting A2: NO. Copper is about the second-best electrical conductor, next to silver. It is also a very Good heat conductor....