Not copper, usually (but they are bare, which was your point).
Around these parts, where the border between L.A. and Beverly Hills is often in the middle of a quiet residential street otherwise the same on either side–the Los Angeles side has utility poles and the Beverly Hills side does not.
Presumably, in California, earthquakes are another consideration.
Marginally related (that should be my catchphrase), at Texas A&M, they run all the utility lines through an undergroudn network of tunnels that used to be used for piping steam used for heating the buildings on campus. They call them the “Steam Tunnels”, and they have some mild notoriety among the students as an ubiquitous forbidden place (large access grates for them are all over the main campus, usually padlocked, and student lore tells of underground “lounges” where students had set up furniture, posters, etc. before the University secured the access points and prevented them from being able to go back below).
This works for the University pretty much because the tunnels were put in long ago, back when there was a heating plant that did nothing but produce lots of steam and pump it through the pipelines to heat the buildings. Now when they run wires or piping or whatever, they tend to put it in conduits running in the tunnels, and expand the steam tunnel network as needed.
I concede your point although I must confess I was thinking about space limitations.
I don’t know. Does it make a difference?
As a Brit visiting the US, one of the things that you immediately notice is all the overhead cables.
I don’t know how much we’re paying for the privilege of not having our eyes offended by the sight of cables everywhere. Utilities are expensive here, and there are endless roadworks, as electricity, communications, water and gas companies try but usually fail to coordinate with each other in the digging up of roads. But I’m still not sure that I would opt for the American system.
My power still arrives from overhead cables here in Surrey.
We get more than our fair share of power cuts too, so much so that when we moved in we bought oil lamps and now I also keep a couple of car batteries charged for additional lighting.
However over the years I’ve managed to learn to ignore the not very attractive sight of the power cables and poles.
Maybe it’s like that out in the Surrey wilderness, but I live in (postal) Surrey too and there are certainly no overhead domestic electricity cables here. In the US they have overhead cables right there in the middle of the city, is my point.
Rarely, in most larger urban areas.
In most areas that are newly developed, wired utilities are usually required to be underground. Main lines may still be above ground, but all new lines must be buried. Areas that are poorer tend not to have mandatory undergrounding for new lines; it’s seen as an impediment to development.
FWIW, the visual clutter of overhead utilities isn’t just an American phenomenon. Toronto is far worse than any US city I’ve visited or lived in, and photos I’ve seen of Australia’s urban built environment show far more utility clutter than the US.
In the Great Lakes region, almost all wired utilities are above ground in Cleveland, while in Buffalo a larger percentage are buried. It’s really noticeable; growing up in Buffalo, power outages were very rare, but in my neighborhood they’re practically a bimonthly occurrence.
According to my university proffessor, underground high voltage cables are a bad idea. Not only they are hugely expensive to lay down in the first place, but also the high voltage degrades the insulation over time so sooner or later those underground cables will have to be unearthed and replaced.
Do you really need to unearth a cable to replace it? Can’t you just pull it out with a replacement tied in? I see the local phone crews replacing buried lines all the time around here, they hardly ever break the road.
If it’s inside a casing, you might be able to pull it out. You will need to dig an access pit, or use an existing junction box/manhole in order to access it.
Casings are usually used here for road crossings. In some areas, utilites are in a tunnel, casing or vault (see above mention of steam tunnels) but it isn’t common here.
:dubious: All utilities have to be periodically replaced. Nothing lasts forever. However, you don’t have to dig the conductors up. You can just pull out the old conductors and replace them. Also, high voltage does not degrade insulation. Heat and age degrades insulation. Either your professor does not know what he is talking about, or you have misconstrued what he said.
Exactly. In all of the areas in which I see buried electric lines, they install access vaults periodically along the route. In fact, they usually install the conduits first, then pull the actual conductors through. Replacing conductors is no big deal, compared to the initial expense of installing the conduits.
I don’t think there’s one standing electrical pole left in Switzerland. It’s part of the esthetic of the country. It shows the cost of burying power lines isn’t unsurmountable.
My high school had buried power lines. The school was on the outskirts of town, basically in the country. Anyways, there were constant power outages in the winter at the school, but not for the neighbouring properties or the town up the road. I recall being told that this was because buried power lines aren’t very useful in areas with a lot of freeze-and-thawing going on.
Is this true, or is it only true of older systems (the school was built in the late 60s, IIRC), or was the school just poorly built, or was this just a complete BS myth that went around the student population to explain why we were freezing our butts off in -20C mid-January?
If the cirumstances allow for corona discharge, the resulting ions will degrade many insulation materials over time.
How is it that a much poorer society was able to do these things a century ago and they cannot do them today? I just read a handsome document prepared for the NYC area. The proposals were wonderful: build the 2nd Ave. subway all the way downtown (with a spur through alphabet city), do something about the Nostrand Junction, a huge bottleneck in Brooklyn, add stops to the Long Island RR, build new rail lines in NJ, on and on. But almost none of it will happen in the forseeable future. All the states and municipalities are broke. (The one thing that is likely to happen is more bus rapid transit, essentially dedicated bus lanes, closed to other traffic.)
Depending upon the voltage used underground cables are also often enclosed in oil filled ducts(at least here in the UK). This is an additional maintenance burden and prevents easy replacement by pulling a new cable through the duct.
We have, as a society, opted for lower taxes instead of infrastructure investment.