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What is "code" for direct burial phone wire?

Discussion in 'Home Power and Microgeneration' started by William P.N. Smith, Nov 22, 2003.

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  1. If I've got some (Cat-5) direct burial cable, and I want to hook up a
    phone wire about 500 feet long, is there any (NEC?) code that
    specifies how deep it has to be buried, or anything else? I figure
    for phone wire it probably doesn't even _have_ to be buried...

  2. Dunno, but phone wire around here going from post to the demarkation point is
    only 6" to 12" down. If the wire were buried much deeper it would be in coral

    Remember that lightning can charge up the ground. Some sort of equipment
    protection might be in order.
  3. j.b. miller

    j.b. miller Guest

    Anything less than 2 feet deep and my plow nicely brings it to the surface!
    the local crew use a 'ditchwitch' kinda machine that burys the phone and
    cable lines about 2 1/2 feet.
    Take some pictures wherever you bury it for reference when you relandscape
    in two years time.
    If you run it through 1 1/4 water pipe( black poly) you'll be able to fish
    something else on a later date too !
  4. Vaughn

    Vaughn Guest

    Good advice! The ditch itself is usually far more expense and problem
    than what you actually put in it. Schedule 40 PVC is a bit better (and more
    expensive) than black tubing, I have seen black poly collapse from soil
    pressures. You can buy "sweep" fittings for conduit at Home Depot that will
    make it easy to pull cable later. If you are truly placing direct-bury
    cable, consider putting the conduit and the cable side-by-side in the trench
    and then you will have the ENTIRE conduit available for whatever later use
    you decide.

    While you are at it...think ahead! Is there anything else you might
    wish later that you had dropped in that trench while it is open? Water?
    Electric? Yard lighting? Sprinklers?

  5. Oh, I agree that if this were for anything more than a temporary
    solution, we'd do a much better job, but this time next year we'll be
    hooked up "properly" with real phone cable in conduit 18" under the
    road, etc.

    We have the opportunity to connect to the line card at our expense
    using our materials for the next year, but it must be "to code",
    whatever that means in the NEC. I've already run the Cat5 direct
    burial cable (buried an inch or two below the surface in places and
    run on the surface in places, but in a PVC pipe where it goes under a
    (golf cart) path. If this is "to code" I'm safe, otherwise I may have
    to rip it out and rent a trencher and operator, and incur hundreds of
    dollars worth of expense.

    Does anyone know if the NEC (or any other applicable code) details
    wire type, size, materials, construction, burial depth, conduit, or
    anything else for telephone wiring? This would be after the Network
    Interface Jack, if that matters.

  6. see:
  7. Dale Farmer

    Dale Farmer Guest

    NEC regards this as low voltage signal cable, and mostly ignores it, as
    it has little impact on safety. Mostly what NEC says is that it cannot be
    in the same conduit with power cables.

  8. Bob Peterson

    Bob Peterson Guest

    I am reasonably sure that the NEC does not even cover such wiring, although
    I could be in error on this point. Cable companies routine bury cables in
    your yard only a few inches underground, so why would telco lines be any
  9. Correct - the phone company buries the line about 6 inches deep across
    my yard, and 18" deep under driveways. Under driveways they like to
    have it in sand - not gravel - and protected with an over-cover, like
    a 2X4.
  10. Guest

    In our area, the local phone company will not give any specifics. I think
    they are trying to avoid liability issues. The installer that came out
    to fish the wire through the conduit said they would have accepted just
    about anything.

    You might try calling the 800 number that the utilities promote for
    locating existing lines and pipes before digging. When they came out for
    us, the told us exactly how deep the cable, water, gas and electrical
    were buried. The locator guy was able to tell us that 18 inches was
    standard for our area. I managed about 16 inches.

    If you bury conduit with the direct burial cable make sure you use sweeps
    at the bends instead of 45 or 90 degree connectors. The sweeps make it
    easy to fish or blow a wire through. The angles of the water pipes are
    a *itch (extreme hassle) to fish through.

    While 1.5 inch seems large, consider 2.5 or 3 inches if you can afford it.
    You don't know today what you may wish to run in 5 years. There's not
    a lot that you can run in 1.5 inch conduit after the first bundle goes in.

    About trenchers.... You can rent a baby Ditch-Witch and trench it yourself
    in a morning. Just don't let the name, "walk behind trencher", fool
    you. I learned that if you walk behind it fills in the trench for you.
    You actually walk backwards and it follows you. It piles the dirt to
    one side. Ask for instructions when you rent it.

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