No power

[glassgowkiss]

wtf? Can't power companies just run the power lines underground? So stupid to keep repairing lines after the storms several times a year.

[burchey]

totally unrelated to this topic - I'm still trying to figure out if I should rip on you or not. I mentor a great kid with a developmental disability. I get a vibe from you that your auto-block might not be engaging all the way, so I'm hesitant to say anything mean moving forward.

 

Am I misreading the situation? Are you functioning "fine", just unbelievably intolerable?

[genepires]

I'm no lineman so I don't have a educated answer to your question but here is a possible rationale. Earthquakes.

 

If and when a earthquake happens, maybe the power lines would be damaged and hard to find and repair the breaks. Above ground lines are easier to repair.

 

With the exception of city environments, it seems that wires on poles supply zones which are feed to houses underground. Not many above ground feeds to homes in rural areas.

 

 

 

 

[AlpineK]

Yep underground lines can fail. Earthquakes are one risk. Joe-bob renting a backhoe for the weekend is another.

 

Utilities spend time figuring out the frequency of disruption along with costs of maintenance. Quite often it comes down to the budget and what they can charge customers for the product. Underground lines often involve jacking utility bills.

 

In a developed area putting in an underground lines is expensive, takes time, and requires maintenance.

 

Overhead lines require maintenance and line clearance or pruning-removing trees.

 

If they can keep odds of failure low then they'll stick with what they've got. Low Risk Does not = No risk

[glassgowkiss]

I know that placing lines underground is $$$, but for fuck sakes how many earthquakes do you have on east coast and how many tornados and hurricanes rip these puppies off several times a year? not to mention snow storms. I am not talking transmission lines, but I bet if you count total cost of repairs in these areas over past 30 years, an underground grid would be half the cost.

[bstach]

I think its alot cheaper to keep repairing them compared to the bug bucks to run them underground. I see them underground in many new neighbourhoods, so i guess if you are already digging things up to install other infrastructure, it makes sense. I would guess there are technical limitations to running high voltage transmission lines underground (i.e. induced currents).

[Crux]

Apparently, with underground power transmission, capacitance is a problem, rather than inductance. (Go figure--RootMeanSqaure, all that.)

 

Fwiw, you can read about it here, in this technical presentation, How many Poles does it take to screw in a light bulb? And for sprayers disinclined to peruse such engineering (and polar geometry) aspects to electrical power, recommended is an article that provides a more direct, current response to the OP's question, answering, It takes four times as many with underground electricity.

 

 

 

[AlpineK]

Yep, new developments put in underground lines. It's code in a lot of cities. If you live in an older community, tough luck sucka.

 

The utilities can't afford it and don't want to deal with all the homeowners and businesses that have their power cut off during instillation and the web of existing underground utilities.

 

It keeps lots of people employed too

 

Asplundh

 

[img:center]http://www.asplundh.com/graphics/Equipment/SideTrimmers.jpg[/img]

[Crux]

I'm wondering where in the system the damage usually occurs. Guessing it occurs locally, rather then over the long distance [very] high voltage power transmission lines that don't do so well underground, from a costs-benefits perspective. In that case, the case that damage typically occurs to the lines right outside your window, or where trees fall, in the lower voltage places like that, it might actually be more practical to go underground?

[G-spotter]

Easily broken isn't bad if it's also easily and cheaply fixed.

 

Tough fixes or extensive damage from breaks, like oil pipelines, require more protection.

[Crux]

[font:Times New Roman]

FA: "The Portland Line"[/font]

 

 

 

[tvashtarkatena]

Underground lines:

 

Are 4 to 15 times more expensive per mile than overhead

Last half as long

Subject those above ground to much higher intensity electrical and magnetic fields

Are far more difficult to repair (pinpointing the damage is much more difficult)

Require noisy and expensive cooling equipment (overhead are, of course, air cooled), which degrades system reliability

Require much more expensive easements

Require much more embodied energy to install

 

to name a few...

 

Much like aid climbing, I'd bet those stupid overhead lines and the idiots who put them up are not going away any time soon.

 

One of the best ways to improve grid efficiency and life cycle cost would be to build DC lines for distances of greater than about 500 miles...above ground, of course.

 

This would also create jobs for overweight aid climbers.

 

I think overhead lines might be less of a visual eyesore if they looked like War of the Worlds attack tripods, but that's probably just me. Perhaps the Burning Man People could design them - it might be the only way to gainfully employ them.

 

 

Edited July 31, 2012 by tvashtarkatena

[whirlwind]

the reason more lines aren't in the ground is the cost of installation. that's where the bulk of the cost is. the power company would rather have the lines in the ground but the cost to rerun lines is not practical, that's why its really only used in new construction areas. the reason why the cost is so expensive is there is a minimum depth they must be, which also has to be above and existing or new water lines. the conductors also need to be a larger in diameter to carry the same current do to heat, also do to heat you can only run a limited number of conductors in the conduit after 4 conductors you need to either increase conductor size or run mulitiple conduit runs (mostly determined by amperage). voltage isn't a bigg issue other then determining the insulation on the wire, the minimum depth requirement also helps absorb the magnetic fields and protect from accidental damage.

 

as far as finding the break, its just as easy, repairing it takes more time do to digging it up, but as long as the installation was good, the likly hood of having an issue is slim to none. minus darwinism of cource (people diggin them up) but then again you more likely to see a downed line from a car or storm, as alot of the underground lines are under streets and or sidewalks, so if someone Diggs one up their yard its only 240volts at the point where it goes to your house, an easy fix, and not likely to kill em, and also will only short the fuse at the transformer, not put the hole city out of power

 

 

[genepires]

240 volts will f@#k you up. 120 volts can f#$k you up too. It is all about current (which is a function of resistance) and current path. small current through the heart will kill. Double the voltage and you double the amperage. (for same resistence) doubling the amperage and you double the chance of being killed. 240v is very dangerous.

 

fuses and breakers are not there to protect people but protect the wiring and prevent fires. relying on fuses in case of electrocution is asking for being fried.

 

I have done some underground work and it usually is in conduit (in commercial and industrial facilities) but I think that the PUD underground wires are direct burial. Which means there is no protection of the wire beyond the outer and inner jackets. I can't imagine the miles and miles of PVC pipe to do the underground work, plus the pull junction boxes. Our backhoes have cut a few of the PUD lines and it is freaky when we do.

[whirlwind]

it depends where they run the cable, yes it is directly barried, but they also use conduit and its usually a good idea in residential settings to do so, especially from the transformer to the house. most the other high voltage lines would be unacessable to the normal public.

240v single phase can kill you, and so can 120v it depends on if the you get stuck on it, have heart condition's, standing in a pool of water ect ect, it usually doesn't kill people.

I dubble check what i work on to make sure its not hot and only work on stuff that is off, unless im checking it with a meter. I said it would kill the fuse not cut power to the city, what i meant was, the outage would be only on the branch circuit which shorted out, and unlikely to affect a lot of other homes. I did not say its ok to work on stuff that is hot cause the fuse will protect you.

 

most people in construction know to check for those type of things before they dig major trenches. as long as conduit is used in residential circumstances, it would not be supper easy to just dig into the line and get shocked.

Edited August 4, 2012 by whirlwind

[genepires]

wire in conduit is meant to be able to change out the wire in the future. Pull it out the pipe and pull in a thicker one if need be. Xfmer to house is a example such as a need to upgrade the service. There is no real protection offered by PVC pipe if using a backhoe or a ditchwitch. (and ditchwitches are easily accessible to residential owners) Once the pvc pieces are flying, the wires are damaged. PVC would definitely protect from damage with a shovel but I doubt that a shovel could damage a wire anyway.

 

From what I have seen, there is no checking for where the underground lines are before digging. Just some low wage laborer watching the bucket at it scrapes away successive layers of dirt. Lack of detailed print of line location and changes to terrain after first burial make it very hard to know where the lines really are. Just dig and rely on the insulation of the big rubber tires is the constructions game plan.

 

I brought up the comments on fuses because there is a general misconception about the protection offered by breakers and fuses.

 

have a good weekend all.

[AlpineK]

Lots of folks don't bother to use it but there is a free information out there.

 

 

[img:center]http://www.callbeforeyoudig.org/images/small_max.jpg[/img]

 

Call before you dig

[whirlwind]

PUD's Know where there lines are and as Feck stated they have a free service. and Conduit is there to protect the conductors from damage, period. in a lot of cases if you want to upgrade you have to upgrade the conduit size as well. but not always. there is a NEC (notational electric code ) standard for number of conductors in a race way, which is determined by the diameter of the conductors and the conduit. If you oversize your conduit in your initial install then you can simply run larger conductors in the future. if not you may have to upgrade both.

[genepires]

 

PUD don't know exactly where the lines are. They have a rough idea of where they are but not close enough when it is time to dig. Anyone who has done underground work knows this.

 

NEC =national electrical code not notational elec code

 

BS on the conduit for protection only. otherwise everything would be romex or MC cable which is protected. Why do commercial operations want emt over other cheaper alternatives? The answer is remodel and future upgrades (which means upsizing or adding wires ), not some greater protection offered by EMT.

 

 

sorry y'all about the electrical geeky thang going on.

Edited August 4, 2012 by genepires

[whirlwind]

ok man. 2 things though you cant use romex were its exposed because its not considered protected, and mc cable cost atleast 2 times as much, probably more depending on the circumstances, then it does to run hard pipe,EMT or other, and pull conductors. I have priced this out, ran a new service installed new circuits in my shop last year. by the way mc cable is considered protected and you can run it exposed.

 

I could be wrong about PUD knowing exactly where there lines are, but I'm pretty sure they can trace them pretty well. and you said you never call them anyway.

 

just a side note, i just graduated from a tech school electrician program with a 3.99 gpa. I'm still learning, but I know the code book pretty well. if you want to get a beer I'd be happy to show you the exact rules when it comes to running conductors, according to the NEC.

[genepires]

I may be wrong but I don't remember any discussion about exposed conductors. Talking about protection of conductors.

 

I never said I never call them. It is not my job to, but the foreman's job to. he lays out where the PUD says the line is but it is a fairly broad area with estimates for depth. And you gotta get the line dug so you dig gently. The one time we hit a line, it wasn;t even on the PUD print for the facility. go figure. There is just no way around it. When you dig, you dig carefully. If it is not a power line, it is the plumbing, or data or irrigation or drainage or some other thing buried. The ground is full of crap.

 

There is no way that running MC cable is more expensive than the labor intensive aspect of bending pipe and coming back later for the wire pull. Don't know about materials costs but I do know that it takes about 5 minutes to put in some 20 feet of MC cable and it takes 25 minutes to lay in the EMT and another 5 minutes to pull in the wire later on. ( for a complex framed wall with lots of typical wall BS to go around) 5 minutes labor vs 30 minutes labor at a bill rate of $60/hr. Plus 10' EMT (plus coupling and a 1 hole strap) costs about $6.5 at lowes plus the wire which is fairly cheap for 10'. So MC cable would have to run at more than $47 ($13 for pipe, $4 for wire, $30 for labor) to be considered "pricey". I seriously doubt that MC > $2.50/ft. (just checked lowes and it runs at 50 cents/ft)

 

just as a side note since you brought it up, but I am a journeyman inside electrician with a admin cert so I have quite a bit experience with the NEC. I know exactly what you are talking about and I know how the industry works. I would be happy to buy you a beer sometime.

 

FWIW, when you take your state exams, the NEC portion is easy. study like mad for the WAC/RCW test. That document is "wack".

Edited August 5, 2012 by genepires

[genepires]

surprised that someone else hasn't jumped on board and given us flack for geeking out.

 

maybe everyone else is climbing this fine weekend.

[whirlwind]

OK but ur talking about running one branch circuit, with mc in which case ur right. if you have multiple circuits its cheaper to run emt, bending and pulling wire takes a little longer, but u can run 3-6 branch circuits in a 1/2 emt, with #12 wire. (fill is 13 conductors) mc cable standard is 3 or 4 wire, which basically is 2 circuits max.

the best way to do it is run emt, then use mc from your junction box, for individual circuts.

 

I'll take that beer anytime.

 

[genepires]

alright you are really full of crap at night. max fill is 9 12awg thhn in 1/2 emt. table c.1 nec. And if I had to pull more than a full boat in a 1/2 emt, I would be kicking some ass or at least giving a verbal smack down.

 

I never said homeruns where best as MC. you were talking about how EMT is cheaper than MC. If you want a real discussion, try to stay on track instead of jumping around to topics you think you know about.

 

MC is widely available in 1,2 or 3 circuits.

 

Don't know how much you have been working in the trade before your accident, but maybe you should get more experience before acting like you know everything. I don't even consider myself an expert compared to my co workers, but the flaws in your statements are easy to find.

 

anyway I am done with this cute little blah blah of "look how smart I am".

 

good luck in the field.

[skykilo]

I been snorting lots of Corona Dope lately. I feel mighty stupid trying to run a LN2-cooled 128 pixel-segmented Si detector in a 5,000 Gauss magnetic field with 30,000 Volts of bias applied to it.

 

Indeed, good luck in the field! Here's to the enslavement of electrons.