[TowerTalk] more pulling cables

[Grant Saviers]

Sand around any conduit/pipe in rocky soil is a good practice.  At my WA 
QTH any holes would let water in even if the conduit was barely covered 
with dirt.  I tried simultaneous pull & glue once and wouldn't do that 
again.  It's just to messy and dirty and risks gluing the cable to the 
conduit.  I put in 2" conduit for power and 3" or 4" for coax and 
control lines.  Code says they need to be at different depths if in the 
same trench, but....

You might consider fiberglass/plastic enclosures rather than steel - no 
rust and much easier to punch or drill for 4" conduit.  check McMaster 
and ebay.  They can't be too big considering junctions, service loops, 
surge arrestors  for rotators & steppIRs, grounding plates, etc.

Something not mentioned so far in these posts is the ability to use 
continuous run conduit.  Your local underground horizontal drilling 
contractor would probably cut off a chunk from his giant spool and might 
have some short ends for free.  I was left several pieces 30 to 60' long 
after a new primary line was run to the new transformer and new service 
runs to generator, house, and shop.  Regular couplings work sch 40 or 
80.  Unfortunately my scraps are sch 80 which takes 3 men and a gorilla 
to straighten on any day less than 80 deg.  Drilling and continuous 
conduit has the advantage of a smooth interior and going around and 
under stuff like driveways, but is not cheap.

And one more input - sweeps are available in various bend radii for 2" 
and larger conduit.  I've seen two radius sizes at HD, and electrical 
suppliers carry larger radii.  IIRC Puget Sound Energy wants 48" radius 
on the service entrance ends and limits how many of these (3?) are 
permitted in a run.  Sometimes sch 80 is required for exiting from 
underground for extra strength to the box/meter. Again, I've seen random 
sch 80 sweeps at HD which they deny they stock.

Grant KZ1W


On 2/25/2013 8:35 PM, Steve K7AWB wrote:
> This April, I will install my conduit and pull the cables to the 
> existing towers.  From the shack
> wall, its about 100 feet to Tower #1 and an additional 130 feet to 
> Tower #2.
> I live on 20 acres.
>
> The cables to Tower #1 will terminate in a steel enclosure at the 
> bottom of
> that tower.  Also, the cables to the far Tower #2 will terminate in a 
> steel
> enclosure at the base of Tower #1 and then continue to Tower #2 in 
> their conduit.
> I probably will use three of the 4" PVC conduits for all the cables
> to get to Tower #1.  One will contain the cables for Tower #1 use; 
> another
> for Tower #2 use; and the third for future projects in the back field. 
> Then
> one additional conduit goes from Tower #1 to Tower #2.  Ands one 
> additional goes in another
> direction also from Tower #1 for future area in the back field.
>
> I figure to glue and bury the conduit in the ground first and put sand,
> dirt, & rock on top of it so pulling cables will not pull the conduit 
> out of the
> ground rather that gluing each section, one at a time, around the cables.
>
> Is burying the conduit before pulling a good idea like I suggest? 
> After all,
> once it is buried, it is impossible to remove it economically.  I will 
> use
> sand to create a smooth bottom for the conduits to rest on and then cover
> them with dirt.  Its all fractured basalt out there, but the back hoe 
> that
> was used managed to make the trenches. The trenches are about 24" deep or
> so.
>
> I know this has been discussed before, but I still have not decided on
> drilling or not a few water holes in the bottom every so often, or at 
> least
> at the lowest spots, to drain water from condensation.  Holes bring bugs
> which  may or may not matter.  I don't want a small hole to become an
> enlarged entrance hole for a Vole which I have out there.
>
> Any suggestions would be welcome.
>
> Steve Sala
> K7AWB
> DN17es
> Nine Mile Falls, WA
>
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