outlet vs switchboard

outlet

noun
  • A wall-mounted device such as a socket or receptacle connected to an electrical system at which current is taken to supply utilization equipment or appliances. 

  • A vent or similar passage to allow the escape of something. 

  • A river that runs out of a lake. 

  • Something which allows for the release of one's desires. 

  • A shop that sells the products of a particular manufacturer or supplier. 

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. 

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