insulator

noun

1. A substance that does not transmit heat (thermal insulator), sound (acoustic insulator) or electricity (electrical insulator).
2. A non-conductive structure, coating or device that does not transmit sound, heat or electricity (see image)

   “To isolate electrical wires from the pylons supporting them, one often uses glass insulators.”

3. A person who installs insulation.

   “Alan Vasen worked as an insulator at this site from September 1968 through mid-April 1969. Mr. Vasen installed thousands of lineal feet of asbestos pipe covering and thousands of square feet of asbestos block insulation throughout the operating units of the Benicia refinery.”