How electric poles are distributed and placed

Question

Complete newbie to anything electricity-related so would appreciate an answer I could easily understand!

I'm wondering how electric poles are placed around an area by an electric utility company?

Are they distributed across an area in a way that benefits any party in any way like saving energy, saving on poles construction or what not?

Also I'm guessing as an area progresses and new buildings are built I'm sure the way the poles were initially placed is not as optimal as it could be for the new buildings around. Is this a common practice of rearranging the poles to better fit the new changes? Do electric companies do this often? Is it cost-effective for them to find the best new "layout" to replace the poles? How do they do that, if ever?

Answer 1

Just to be clear, we're talking about medium and low-voltage distribution poles that are shared with other utilities, not high-voltage pylons.

If there are no property constraints, the utility will space the poles as wide as cable droop (sometimes called 'catenary', for the shape of the droop) would allow: up to 300 feet in rural areas.

Generally though they will place poles on property boundaries, in coordination with local planning / zoning authorities. They will place them frequently enough so that down-feed connections to nearby homes are realistic. This works out to about 125 feet typically.

Related question here: Low voltage power lines - formula for spacing between poles?