mains vs wattage

mains

noun
  • The domestic electrical power supply. 

  • The pipes of a centralized water supply that transport the water to individual buildings. 

  • The farm attached to a mansion house. 

  • The main course of a meal. 

wattage

noun
  • The power requirement of some electric appliance. 

  • An amount or power (especially electric), expressed in watts, kilowatts etc. 

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