Hello, I have about 3000ft of trenching to do in order to pass a direct burial 5000V wire to my residence. I'm debating where I should trench. It will be 3ft deep and I will have to bring in clean sand to put on top. My driveway isn't finished yet, it still needs about 3 inch of 0-3/4 stone on top of what you see. I could dig right in the middle of the driveway. Pros: -I know there isn't any boulder -I need to put clean sand over the wire so it would be put to good use -allow me to use excavated material to build a better crown before finishing the driveway Cons: -I damage my driveway My initial tough was to dig in the ditch Pros: -I don't break the driveway -I can clean them up at the same time Cons: -harder to dig -I am sure there is some huge rock over there, there is even a spot that the bedrock is touching the surface... I can add a conduit for a few spot but it would be too expensive if needed almost everywhere So, where would you dig if it was your home? I will probably rent a mini ex because I want a narrow bucket (8inch) finally the soil is sandy rock, clay doesn't exist here! thanks Alexis
if it was my house i would put it in pipe and probably dig it to the side.
I would trench down the center. You know there are no boulders there. I don't know how you could "damage" your driveway. After all, it's just dirt and rocks. You should also look into renting an actual trencher. It will be a pain to dig and move, dig and move, dig and move ect. Especially for 3000 feet. The trencher can just keep on the move.
I'd chain trench it, center of the road and go 48" down and put tape in 12" above the line and 24" above just because you might want to re-grade the drive sometime. I'd also put it in conduit, its cheap compared to diging it all up again if you ever have a problem.
Ive had bad luck with trenchers, walk along ditch witch kind. Ive used them for irrigation and gas services. Using the chain seems every rock it hit if I was quick enough to raise the chain or stop it, the machine would stall. That was in sandy gravel material with rocks not very big. If it was me I'd go right up the edge of the drive way giving yourself enough room to be able to walk the machine through leaving yourself able to sand after your done if you wanted to and not as you go. You didnt say anything about paving so I wouldnt worry much about settling as long as you do some sort of good compaction. A mini excavator with a clean up bucket would be my choice. Dig it, swap to the clean up bucket, then walk along side the trench with it sanding. Swap back to the dig bucket, straddle the trench put a lift on top the sand, compact however, tape it. Swap back to the clean up and backfill the rest. If you happen to have a skid steer as well, leaving enough room to drive along side the trench, youd be able pick up any rocks thrown off to the side and maybe even sand with it depending on how your set up. At work we do everything with a back hoe. Cant drive in 90degree angle on a job like that so I'd plan to dig the trench in a spot I could straddle the trench drive up and shovel sand out the front bucket. Then put a lift in with the back end.
Who owns the cable? Out here on the left coast, I paid for the cable and installation. Once the utility approved it, they own it and the maintenance if it ever craps out. So conduit would be a big, needless expense if the utility owns the cable after you bury it. They have equipment to locate exactly where the break is, even down 3 feet, under an asphalt driveway. I watched them do it.... I'd go with a trencher, as big as you can afford. I dug 1000 feet with the hoe, wished I'd rented a trencher.
Jeeze....and I thought my power run was long! I would go with a large ride-on trencher right down the middle. You can deal with settling better in the middle than on one side or the other. I'll do your 3000' if you do my 1800'.
i would also add make the drive wider that is snow country if you have alot of snow and plow it there will be no room left and or your will end up in that side run off area which will require a tow out. i know it's a long run but unless your not using it durning the winter months i would do that then no problem where to put lines but definatly in pipe and beded in sand . they just redid my entire neiborhood because suprise no pipe rocks seam to work there way up and sever wire .
thanks for the answer, I'm glad people suggested a trencher. It was my first choice but I tought it wouldn't work since it's not clean sand... there is rock the size of my fist but if the trencher can work, it's no doubt best! The electric line will be owned by me. The hydro company wanted 42K to do overhead cable with 50ft of tree cleared by me. They wanted 56K to do underground! It will cost me 12K plus the sand to do my line underground! Can someone give me a ballpart idea of the cost of conduit? The electrician said I didn't need it but if it's best and no overly expensive, I will put it. For the driveway width... this driveway have been a big big big expense. It was supposed to cost me 23K and ended up like you see it at 40K! This project showed me that I need to buy a loader backhoe since I will need a few other road to go to some future barn building. I just want it to be finished and in a few years, I will be able to make it better but for now, I've already putted twice what I tought it would cost me! So again thanks for you answer, I'll make a few call to see if there is a big trencher available to rent and I will dig in the middle of the driveway. A last question: if I put conduit, I suppose I don't have to bring clean sand to go on top... I'll ask my electrician also. thanks Alexis
Yes, check with your electrician. My hydro company wants clean fill or clean existing fill (if good enough) around the conduit. Basically saying to keep the larger rocks away from the conduit.
How do you know there are no rocks in the driveway? I say this because my logging roads are built much like your driveway, in the same type of ground in the same hardwood stands. We load the rocks into the road to gain height, and that looks like what has been done here, as the ditches aren't littered with rocks. Where did the stumps go? Also standard practice to put them in the road. Unless you built the road yourself or supervised it with your own eyes, you may be surprised at what is in that roadbed. A trencher may be a pipe dream, no pun intended. I'm just trying to help you avoid frustration and disappointment.
There is a few rocks in the driveway and no stumps, I was there for most of the construction. I called all the renting shop around here and they only have small 12inch trencher so this idea won't work... Also the tubing is 1.10 per feet and the electrician says that the wire is a very resistant wire that is hard to cut with metal snips so it doesn't need to be protected. I think I will just tak e the 3500$ rebate and forget the tubing. I think I will need to search for a narrow bucket for the tlb...
Are you sure you can use conduit? Sounds like high voltage to feed a transformer. Power Co. here requires sand for that it's considered primary line. jr
yes I need sand, i checked with the electrician, 3' on top because it will be 6000 volt
Another thing better check with power co. they may not want it in your roadway. jr
I would go down the middle of your drive. Much easier and faster digging than in the ditch. The backfill sand will compact quickly, and as you said, the excavated material can be used to crown the roadbed before you have gravel brought in.
How about cleaning up the downslope side of the entire roadway about four feet out from the edge ? Then lay the bedding sand right at the toe of your existing road , then lay the pipe on it , cover it with enough sand to protect it. That way you would have the entire width of your existing road to bring enough fill material to cover it and at the same time you will end up with a road that would be about three or four feet wider than it is now. The real advantage of laying it alongside the existing road is that you will always be able to do any maintenance to the pipe and wire and still have full use of your road.
there's always directional drilling. If they allow it, I've done a few. Mostly under parking lots . which ever way you decide, bury spare pipe, most all businesses always double actual pipe needed. If some thing would happen to the cable, like burn and fuse to the pipe, the spare can be used, with out retrenching a new line.
thanks for all the answer, I tried all the places: no big trenchers are available to rent. I also checked with my electrician, he is not a fan of conduit. He says that to be usefull, I would need close to 10 pull box and that the new coating on the wire makes them almost last forever if you don't cut it with a machine. So, I'll dig in the middle of the driveway and do direct burial cause I need to save money where I can I'll rent a min ex for a few day and do the job myself Thanks for all the suggestions Alexis
That 10 pull box comment is making me worry about my 1800' run. Not counting the power pole and transformer the power engineer only specified 2 pull boxes for 3" conduit. Is your wire a single coax arrangement?
I think 600' is about max for pull boxes.
To be honest i think he just does not want to do the pull. but i guess if you back fill with alot of sand around it it should be ok the electric co just got done doing pipe here because of that dirct burial we had all kinds of proplems with it going off.
Alexis, I may be a bit late on this one, however I would not trench down your driveway if I were you. I have worked for various Utilities for a lot of years and seen many people open trenches for power/water/gas/comms down their driveways to reach a building in an otherwise difficult spot. Looking at your photos, erosion will be your worst enemy with the slope. I have personally laid pipes/cables in trenches 1200-1500mm deep down sloping driveways (from 100m-2000m long) and then within 3 years been back to repair damaged pipes/cables in the same driveway that were being run over as they were near or at the surface due to erosion. Once you open a trench in a driveway, it is extremely difficult to get the same compaction as the surrounding soil once backfilled and a combination of rain, vehicle movements and the gradient washes all the soil out. If you are going to direct bury, you will definitely need to bed the trench (and backfill) with clean sand which will add to the erosion problems.The water runs down the trench like a river bed. I think you have a few options: 1. Dig down driveway, backfill and then tarmac or concrete driveway, 2. Dig down side of driveway, lay conduit and hauling pits, pour concrete over conduit where you are unable to bury to provide protection, 3. Find alternative route to trench which may involve clearing, however it may shorten the distance to the house and erosion will not be a major concern. Worst case, if the cable is exposed, you won't be running over it. The last thing you want to be doing is grading/backblading your driveway and hit a live, direct buried power cable just below the surface. Karl
thanks for the advice rally action, but could you clarify for me? I don't understand how a wire buried 3 feet underground can come back to the surface. This is a road that will be maintained and will have a gravel finishing course so I don't plan to see a lot of erosion and if there is, it will be immediately repaired, since it's the road for my house... thanks
I'd use a ride on chain trencher right down the middle of the drive and use 4" conduit.
I guess it's safe to assume you have a machine to finish the driveway?
Yes I have, and I plan to keep it top shape!
Karl (Rally Action) brings up a notable point - water movement through trenches. There are a few things that are done to mitigate the effect of such a thing, such as occasional bench drains running to daylight and a few slurry dams. Sometimes on the steep ones, the "cement n sand" slurry 'dams' are revised to a four or five sacks pea gravel and they are keyed into the side of the trench to act as an anchor and a dam for the saturated backfill (which occurs due to movement of water below grade such as post rain or naturally occurring pathways in the soil which are interrupted by us dirt folks. OldandWorn indicated the length of the pull through conduit is thought provoking - we use Polywater's software and their pulling lube of course (conduit cleaning and prelubing, then the saturated swab attached to the pull head and 'painting' the cable with the lube as it enters) and have found pulling forces to be quite predictable. A pull box can be a real obstacle to production because you have to fabricate brackets or mounts on existing brackets and install the pull wheel and then redirect the pull, etc etc. Many times the crew pulls straight through the pull box so one wonders why is that pull box @ $$ is there? If you do actually use the pull box for pulling there is the difficulty in managing all that cable that got pulled out - unless you rent a rubber wheel on wheel powered pull booster which needs a good sized box to fit into. Damaging insulation on a hv cable is a big deal so I can see why some folks chose direct bury, but....our local utility won't allow direct bury ever again, and then there are the third party damage concerns, etc We put the conduit straight and flat like a sewer line, try to buy 20' pipe lengths, keep it clean, and lube it up and always dissuade ourselves from using pull boxes. *** This is great to see so many ideas on doing a project - as for me, I try to think about sanding that ditch (the bottom sand layer has to be flat & compacted to support the cable with no bridging) and how I move equipment by, &/or move say a trailer with the big cable roll, or get the conduit in there if the plan changes, etc etc so I kind of like the idea about using the shoulder area as opposed to straight down the middle.