ring main
noun/ˈrɪŋ meɪn/
/ˈrɪŋ meɪn/
(specialist)- an arrangement of cables that allows electricity to be supplied to a series of places from either of two directions
（电路的）环形干线 - (also ring circuit)(specialist) an arrangement of wires that supply electricity to several different places in a room or building
（电路的）环形干线 - an arrangement of connected pipes that allows water, steam, etc. to enter and leave a system
（管路的）环形主线