I went a bit deeper than 8" (30") . I found a plumbing contractor who could
fit in a special job. He brought a gas powered device that cut a trench
about 15" wide and 30" deep and piled the dirt alongside the trench for easy
replacement.
I put one 4" solid tube PVC and one 3" solid tube PVC run and a 1" EMT run
in the bottom of the trench with access boxes each time I arrived at a tower
base or had to make a turn greater than 20 degrees. There is also an access
box at the house. I covered the access points with a large slab of patio
flagstone which identifies the location but has an XYL acceptable character
in those locations. The access boxes are large Rubbermaid type storage
containers with snap closing covers --approximately 24"x20"x24" ---
located on the bottom of the trench. I built a wood frame slightly larger
than the box and located it above the covered box and then put 1"x4" boards
across the frame. The flagstone rests on the 1" x 4" boards making access
simple. When the box covers are snapped into place the box is essentially
water tight, but not condensate free, so each box has a few drain holes in
the bottom. I tried to get each of my conduit runs to 'drain' into a box by
adjusting the slope of the trench with a shovel. The idea was to get the
condensate to collect in one place.
The three tubes enter and leave each storage container via cut out circles.
The entry and exit points are sealed with bathtub type silicone cement which
is slightly flexible when cured. The EMT has an electrical junction box at
each container and if there is a side hole take out for coax and control
lines to a tower base, there is also an separate exit hole for an EMT
conduit which is piped up to a GFI outlet at the tower base. The cost of
having 117 VAC easily available at every tower is worth every penny. I do
NOT run the AC line in the same conduits that carry the coax and control
lines. Just a personal safety decision.
I use 1/4 black Dacron lines that go in a circle between the storage boxes.
One line leaves by the 3" conduit and returns by the 4" conduit from that
direction. The Dacron line ends are tied together to make it round-and-round
pull line. That reduced the "pull distance" and made getting the several
hardline runs I have into the two conduits much, much easier. I use the
Dacron lines to pull a much lighter line through the conduit. Then I use the
light line to pull a much heavier line which will do the actual hardline,
coax or control line pulling. This guarantees that if the 'pull' line beaks
I still have my round-and-round line in place to pull another 'pulling' line
through.
I suggest that you think of all the things that might go wrong and then have
a way to recover if it happens. It will happen.
When you pull more than about 100 feet of 7/8" hardline through a conduit
you will find that it is nice to have the storage boxes in place so someone
can feed the line in and out at each of the points on the way to the final
destination. If you are a really good planner and never change your mind or
improve on things after your initial design you can simply install all the
lines before burying the conduits and forget about all the rest of my
information above.
Tod, KØTO
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