When you’re piling on electrical infrastructure all around the cities or something else you need to balance power on the network.
Guide to Balance Power
Regardless of whether you use inter-connected or separate lines, I find the best strategy, if you can afford it, is to build your low voltage lines straight through a new town, from one side to another. Build them along the roads but if there are no roads don’t let that stop you.
In the late game, you’re able to drop down multiple substations near a town that isn’t going to need it for a long time, building both these and the LV lines through the town helps ensure you don’t run into a situation where a town is impossible to service because you just can’t get the LV lines in there.
You can’t demolish town buildings (I dont think), so building the lines before the town gets built up helps to ensure you have enough LV lines to meet demand later.
So far I prefer an inter-connected strategy because I find it leads to less micromanagement. If a line or substation gets overloaded I probably just need to add another substation outside city limits.
Also keep in mind that electricity consumption has almost nothing to do with the size of the building. Sometimes the opposite. So use the power demand view (not the line utilization view) to see what is going on. Sometimes you want to build one substation just to get it to a hospital and that’s it.