Ask New York City. It’s expensive af every time a change needs to be made underground because you have to dig everything up, and once you’re down there, it’s just a nest of wires in conduit so knowing which one you’re supposed to work on can be a challenge.
Underground wires have to be insulated to prevent short circuits to ground. The longer a wire needs to go, and the more power it needs to carry, the thicker it needs to be. Since insulation goes around the outside, this increases exponentially and the cable quickly becomes mostly insulation in many cases, which is expensive and inefficient.
Also, there’s only so much ground you can dig up before you hit bedrock. So, in some cases, power infrastructure expansion is limited because there’s nowhere to bury the wires.
In many places it’s easier to let the damage happen and repair it cheaply.
Yet in London, power lines are buried, alongside gas and water supplies and most of the telephony network.
Its a choice about what cost is acxeptable for the long term benefits of protection from the elements and safety generally. It costs more upfront, but extends the lifespan of cables as theyre protected from temperatures, UV, fainfall, and falling tree branches.
When they do need repair / replacement it requires digging but theyre generally subsurface, and many utilities are under pavements or to one side of the road, allowing roads to be kept partially open. But they generally require repair less frequently than exposed cabling.
fiber optics solve most of this for comms. clearly doesn’t help for electricity.
Why do they have to be dug back up? Would it not be possible to make an extra level for all cables when you dig for sewers or subways?
This also solves the grounding problem.
If you only want to do the minimum for every change then yeah, just put it above ground, but that’s how business works, governments are suppose to plan long term.
Because then all the phone calls would have sounded muffled.
Couldn’t you just yell a little louder into the phone to make up for it?
You’re thinking of “too quite” which can be solved with louder speech. Muffled remains unclear regardless of volume.
Incorrect. “Too quite” can only be cancelled out by some “not very”.
deleted by creator
In australia buried lines are fairly common. It’s more expense and harder to do maintainence, but it’s also way better and safer.
Perth started burying their lines in the 90s. It was supposed to take 30 years. Last I heard, they’re about half done.
Yeah i was in high school in perth in the 90s so i remember poles disappearing.
Perth has expanded massively in the last 10-15 years, i’m not surprised initial estimates were way off. Or even less surprised than normal since i believe every single infrastructure project in history has been late and overbudget.
There were supposed to be five pyramids at Giza. Cutbacks…
j/k
Bet the power stays on more during storms and shit as well.
Poles get knocked over, struck by lightning, trees, blah blah.
Where I live, ground settling causes problems with utilities. Gas company had to come last week to redo line to my house because it had dropped a foot.
More expensive to build. That doesn’t get offset by accidents and whatever. Also harder to repair in case something really is broken with it.
Very very expensive. For fiber, though, it’s starting to make sense economically.
In addition to cost (as everyone else said), work and worker qualifications. Working on underground lines requires special confined spaces training and certification, because it is more dangerous, could deal with not just electricity, but potentially hight temperatures, water, sewage, toxic gas, lack of oxygen, etc. There are even fewer people willing to do that compared to riding a bucket to the overhead lines.
Source: Worked for electrical utility
High population of native predators:
$$$
Here they are for residential supply. It’s been this way for almost 50 years.
For high voltage AC, underground cabling is actually a nightmare from a maintenance perspective.
There’s 3 answers.
- It’s shitty to maintain underground wiring and it’s shitty to trench it in the first place, so while you are saving money in the long run, you’re paying upfront to run it and your routine maintenance costs are higher in short bursts instead of lower cost per issue, but a lot more issues. This makes people angry the money line didn’t go up enough that month and now you’re fired… even though you saved them money in the long run.
- You can’t run it very far underground. I won’t get into the physics, but suffice it to say, running power underground tends to be “leaky”, and it will bleed away very quickly over relatively short distances.
- Sunk Costs. Tech for trenching and boring has gotten a lot better, it costs less to do than it did 100 years ago, but moving the lines now and tearing down the old ones would cost money upfront and no one wants to pay for that.
In the city i live in (Victoria, BC) the wealthiest part of town has buried lines. Everywhere else, they’re on poles.
Some unprepared countries tried this, in an effort to modernize. Without interdeparrment communication, good documentation, coordination, signage and, well, maps that included depth data that are maintained and updated in real time, yould have frequent outages each time one works department or private contractor did some digging in an inocuous patch.
Source: am malaysian.
The poors get overhead lines, the wealthy get underground
We used to insulate cables with basically waxy paper, not exactly the most waterproof of materials, and if you want to bury lines long term you need to enclose the sections in some kind of corrosion resistant waterproof pipe so you don’t have to dig them up completely every time you need to do maintenance
So this really wasn’t a practical option until petrochemicals came onto the scene, but also the improvements to metallurgy and grid technology were probably necessary to really make this feasible
Imagine trying to track down shorts underground constantly…
That’s not exactly true. The first undersea transatlantic cable was laid in 1854, well before petrochemical coatings. Admittedly, it didn’t last long. But the third cable in 1866 did last quite a while.
The cables were coated in gutta-percha.
This is undersea cabling, not underground, but saying we used to coat them in waxy paper is what I would disagree with.
That’s interesting, but also a special case. Those were specifically underwater cables, they needed to be kept wet
And even after we created rubber, we definitely did not coat normal cables in rubber, ever since the properties of latex were discovered we’ve basically never had enough to fully meet the demand. Rubber is really useful for all sorts of things, and latex trees take a decade to start producing and only produce for another couple decades. Discovering alternatives using petrochemicals was a really big deal because of that
My point stands… The wires we used for early electricity and telephone transmission had minimal insulation, if any at all. Definitely nothing suitable to use underground until much later. Here’s a breakdown of the time frames for insulation (and note that cost was a significant part of the decision, even today we don’t use weather proof insulation unless the situation calls for it)
In the 1880’s the first insulated cables were insulated with gutta percha, a natural latex material produced from the sap of trees of the same name. This insulation needed to be kept constantly wet or it would dry out and fail to insulate the conductors. This material was largely replaced by rubber and vulcanised bitumen.
By the 1890’s mass impregnated paper insulation was being used on cables and voltages as high as 10kV.
In 1906 armoured cables were introduced which had flexible sheathing and two cloth covered, rubber insulated conductors.
In the 1930’s the first trials with PVC insulations were being made in Germany and by the end of the second world war there were significant varieties of synthetic rubbers and polyethylene.
By the 1950’s PVC was commercially viable and replaced rubber cables in many areas particularly in domestic wiring, aluminium was also starting to be used widely as an alternative conductor
The 1970’s heralded XLPE insulations replacing paper insulated cables in medium voltage applications.
In the 1980’s optical fibres were being introduced in overhead lines for data transmission and condition monitoring, and further use of XLPE in high voltage transmission lines between 66 and 240kV. Also high temperature super conductivity materials were discovered. PVC alternatives (LSZH cables) which were safer in fires were being developed in response to a number of tragic public fires which demonstrated the dangers of smoke and toxic gases from various materials including PVC’s.
By the 1990’s polymers were being extended to use in EHV, extra high voltage, applications and the use of optical fibres in overhead lines was becoming widespread.
Don’t know why they don’t this in your place. Here, power, phone, fiber, everything is underground for years now.
