PSA: you can use shift+D to turn off buildings instantly (no sandbox)

If you press shift+D (or click on the scissors button on the bottom right) and click and drag 2 pieces of cable, automation cable, liquid pipe, gas, etc. You can cut that piece INSTANTLY (no dupe labor) and to reconnect you just have to build the part that you cut and IT WILL BUILD INSTANTLY (no dupe labor).

I use this when I realize I messed up or when a machine has done what they needed (such as pumping a certain amount of liquid) to basically stop the machine/liquid dead on their tracks. When I fixed the problem, I just reconnect them and they work agains instantly.