power strip vs relocatable power tap

power strip

noun
  • A block of electrical sockets that attaches to the end of a flexible cable and allows multiple electrical devices to be plugged in. 

relocatable power tap

noun
  • A multi-socket power cord that can be used to channel electricity from a single socket. 

How often have the words power strip and relocatable power tap occurred in a corpus of books? (source: Google Ngram Viewer )