disconnector vs isolator

disconnector

noun
  • A switching device used to open an electric circuit when there is no current through it. They are used to isolate a part of an electrical system to allow the maintenance staff a safe access to it. 

isolator

noun
  • An electrical device that detects short circuits and isolates them. 

  • A device that isolates something from the surrounding environment to keep it sterile. 

  • A transparent box for holding small live animals. 

How often have the words disconnector and isolator occurred in a corpus of books? (source: Google Ngram Viewer )