Underground vs Overhead Utilities

[sly isle]

So, this one is for the engineers out there in the <@&787910105185124392> group, because I’m super curious. One reason that electric utilities try to go overhead rather than underground is because of the huge cost associated with under grounding, typically 10x more per mile and even greater if soils are poor. But if gas lines can be bored underground which saves so much money, why can’t electric.

Still trying to figure this one out at my utility and no one has an answer so thought I’d ask the group their opinions!

[hazy helm]

That's a very good question and now I'm interested in the answer as well

[hollow atlas]

@sly isle well the main reason isn’t just the cost involved with drilling electrical lines underground but the main reason they are overground: heat dissipation

[sly isle]

For those who may not be aware, I’ll also add, under grounding helps to protect the system from animals, plants, and other outside disruptions that typically cause outages. It’s safer because a down line wouldn’t occur and therefore be exposed to people and threaten their safety. On the other hand, fixes are more costly because you have to find and dig up the break. Also the natural cooling effect of the air is not present underground and therefore needs alternatives

[hollow atlas]

Oh you just said it lol

And it’s not a complete guarantee as Hurricane Sandy ended up flooding and damaging underground power lines anyways

[sly isle]

Yes, it’s give and take regarding those factors. And at least with my utility, undergrounding electrical is usually more common in the cities. We do it, just don’t like it and the cost is the big reason I hear.

[sly isle]

Damage can still occur, of course, but they are way more protected then overhead which is exposed to everything

For example, the most common outage on our systems, birds and squirrels getting into transformers and causing a short (at their own expense)

Never mind trees are known to snap lines, or they can catch fire in dry months from touching a line, or can act as a grounding rod and zap power from the system. Underground lines are insulated and better protected.

[elfin ledge]

Me too, especially since above ground isnt that common around here

[rocky robin]

The main reason is the cost of undergrounding. In the cities I have worked for, the developer was responsible for undergrounding the electrical lines, but the transformers had to to stay above ground. The electrical company explained that while a city may want an underground transformer vault for design reasons it poses a serious risk for workers in case of electrical explosions or discharge.

One city I worked for actually had a waiver process for undergrounding electrical lines that an applicant can apply for because the cost could make the project unbuildable.

[sly isle]

Yes, as mentioned before, undergrounding has a huge price tag (as mentioned before) but the point I’m trying to make is technology like boring can help reduce those cost (as shown in boring gas lines). I’m wondering if there are technical issues with boring electrical infrastructure compared to other utilities?

Yes, some equipment must remain above ground too, but they don’t consume huge quantities of space. They also don’t create the same unsightly scene of above ground utility poles with a bunch of equipment strapped to them. And lines going everywhere

Furthermore, you don’t have to worry about chemically treated wood poles that often attract insects and birds.

[rocky robin]

Got it. I am not an expert but electrical lines need to be relatively close to the surface because of the number of hookups and maintenance required. There is also the issue of existing and old/abounded underground infrastructure. We have run across this before where they found unmarked utilities that were from the turn of the last century. Discovering items like these adds extra costs and time to a project.

However, I can inquire with some coworkers when I get back in the office for a better answer.