Asked on Dec 20, 2011

20 years ago I built a stand alone garage and provided power by burying wires in a PVC conduit.

Rohe's DPS IncGreg Warren FlowersNichter's Home Services Corp


As time went by the conduit was brought to the surface by tree roots and now I must redo the project. Since parts of the property are on bedrock burying to the code depth is impossible and we do not want overhead wires to the garage. Can conduit be placed in the ground in a way to avoid normal regulations concerning depth. I original used direct bury wires and placed them in the conduit for additional protection. Since I did this myself and with an electrically adept friend I never had it inspected. Trying to comply without degrading the look of the property. Dan
7 answers
  • KMS Woodworks
    on Dec 20, 2011

    Is it possible to take a longer route to the garage that avoids the bedrock?...20 or 30 extra feet of wire may be less work than digging through stone. I ran power to my stand alone shed a few years back. I dug by hand and used an air chisel to bust up some of the harder rock areas. Its a bit like work but in the end worth it. As a landscaper do you have easy access to a trencher?

  • You can run it above ground in conduit, perhaps along a fence line. But you cannot simply set it on the ground for risk of damage. If you had it dug under ground in the past and only roots were the issue. Simply cut the roots away.

  • Renting a jackhammer is an option to remove ledge rock. The Bosch Brute electric is the most common. I don't recall exact details, but I believe the code has allowances for reducing required depth if you run in a conduit and pour concrete over the area of reduced depth. My sparky has done this a couple of times

  • KMS Woodworks
    on Dec 21, 2011

    I got to use one of those Bosch Jackhammers this year...first made quick work of some concrete ....just be careful to keep it moving side to side...that tip can dig its way to China in no time.

  • I owned one for years. Probably put over a thousand hours on it. Finally it owned me. I sold it before letting the arthritis get any worse. Never use a jack hammer with only one bit. When ( not if - when) you get the bit stuck, you have another to work in nearby to get it out. I did more rock and ledge than concrete. Crete is easy by comparison. The top 12-18" of ledge is usually more rotten rock that is fairly easy, as frost has generally loosened it over the years

  • Greg Warren Flowers
    on Dec 22, 2011

    Have you checked to see if a heavy metal "rigid" pipe is acceptable?? We were able to use this and pass code at a more shallow depth...the other option they gave us was to encase under concrete, ugh.

  • Rohe's DPS Inc
    on Dec 23, 2011

    Thank you all. In speaking with the solar company that will do the installation we will make the decision on whether to utilize existing conduit and pull a new wire using the existing cable. It requires burying that conduit that roots brought up. He liked that idea better than a new cable through the house to a point within 25 feet of the garage. Busting the granite that we have here is not an option so if the existing plastic conduit cannot be buried to depth the only options are a steel conduit that only needs 6 inches or go through the attic and across. Thank you all, it helped direct the discussion with the solar contractor. Dan

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