switchboard vs wall plug

switchboard

noun
  • A large piece of power-distribution equipment that directs electricity to multiple loads. 

  • The electronic panel that is used to direct telephone calls to the desired recipient. 

wall plug

noun
  • An electric socket. 

  • A fixing that allows screws to be fitted into masonry walls, a dowel or screw anchor. 

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