olemus
elektrivõrgu nimipinge
=
the electrical voltage supplied through mains power distribution; in most regions of the world the mains voltage is 230 V at 50 Hz

ülevaateid
https://en.wikipedia.org/wiki/Mains_electricity

https://en.wikipedia.org/wiki/Mains_electricity_by_country

http://www.sailwider-smartpower.com/articles/electricity-standards-around-the-world.htm

vt ka
https://english.stackexchange.com/questions/392461/why-is-home-electricity-supply-called-mains