Can you explain more about the expected maintenance costs per foot for each? I would imagine that the average maintenance cost for an underground line is lower, but there is a much greater risk of an extremely high maintenance cost in the event of repairing water infiltration or damage from construction. So that if overhead lines have an average maintenance cost of X/[ft*yr], underground lines might have an average of .75X/[ft*yr] but sometimes as high as 5X/[ft*yr]. Or are underground lines always more expensive to maintain? Also what about flexibility? It seems that underground lines might be ideal in a master planned community where there isn't really any expected change in the density of development. Whereas in a less formally planned community, or in the exurbs where new development may happen a few years in the future, the ability to just slap a new pole pig on an existing pole would be very useful.
