This is very common in areas that have an Orthodox community. For those who don’t know, the ‘wires’ are pretty much invisible to the goyish eye. But there’s always a fuss from town councils, I don’t know why. To me, it adds a nice bit of cultural diversity without any of the dark sides associated with it.
In many cases (most?) they use existing wires, you'd have to know which utility wire was designated. I live in an Eruv, I couldn't point out the designated wires if my life depended on it. Most non observant and non Jewish, probably the majority in the Eruvs I'm aware of in the Chicago area, haven't a clue they live in one.