mainnoun(PIPE)

the mains

phraseUK
the place at which outside pipes or wires carrying water, electricity, etc. connect with the system inside a house or building: 内外管道相接处;总阀门;总电源
Switch off the electricity at the mains before starting work.工作前要先关闭总电源。
I struggled to find the mains switch.
Make sure you have turned the water off at the mains.
The mains tap is located under the sink.
Turn the electricity back on at the mains.
See also