As a construction Electrician the past 25 years, the only thing I can add
to Tod's install is to pull a #10 or #10 stranded THHN wire in the conduit,
instead of a rope, or string. It's been my experience, that using a string
or rope for future pulls is not a good idea. The rope will ALWAYS wrap
around other cables, and when you pull it out, it WILL burn thru insulation.
If you use a wire ( and lots of lube like Tod says), it'll slip right past
the others.
Hi idea of separating the 120 volts from the other cables is GREAT idea
also. Plus, the electrical code prohibits that, unless the insulation on the
control cable is rated for same voltage ( i.e. 600 volts).
Tod, sounds like a great install! I would follow his advice!
73- Chuck KI9A
In a message dated 7/27/2009 7:03:27 P.M. Central Daylight Time,
tod@k0to.us writes:
Larry:
The really good ideas have already been expressed. I have a couple of
things
that you might want to consider if your particular layout makes them
sensible. I
have a 200 foot run from the house to the base of the HF tower. On the way
I
make "stops" for other antenna locations. There are two bends in the run.
1. I hired an under-employed plumber to use his trencher to make a three
foot
deep 18" wide trench. The cost was nominal and might be reduced if you
rent one
and do it yourself.
2. I used one 3" and one 4" white PVC conduit designed for carrying water
[from
Home Depot] for the combination of hard lines [3 each 3/4" diam, 3 each
1/2"
diam] and control cables [2 rotator, 2 14-conductor cables] PLUS a separate
electrical conduit that carries 117 vac to each of the tower bases. I
deliberately separated the 117 vac to avoid potential problems.
3. At each tower base GFI outlets are installed to provide convenient
power.
4. At each bend I installed a large Rubbermaid box, 20 gallon or so. I cut
holes
in the boxes for each size of conduit to enter at one end and exit at the
other.
I used silicone adhesive to seal the box-conduit junctions. I built a frame
[using redwood or treated wood to avoid rotting] to keep the dirt away
from the
top area of the box and then covered the frame with wood boards. Finally,
I put
a large piece of flagstone over the top of each box. The location of the
boxes
is easy to find and even though they are in the middle of my lawn my wife
is not
troubled by them. The runs slope upward from the boxes so that water
entering
the conduits flows to the boxes. I perforated the bottom of each box with
several holes to allow the water to seep into the ground below the box.
5. I inserted a length of 1/8" Dacron rope in each of the large conduits
and
then tied the ends together. When I pull on one side the cord on the other
side
moves too. The maximum length of a single run is 70 feet. I used the 1/8"
round-and-round cord to pull another line through one on the conduits.
That new
line is used to pull additional control lines and CATV lines.
6. Since the length of each PVC section was 10 feet I had to assemble
lengths
into the run lengths I needed. At the time I installed the conduits I
inserted
the CATV hard line and control cables as I built the conduit. No pulling
was
required. Naturally, after I started operating the system I found I wanted
more
feed lines and control lines. That was when I was happy I had inserted the
round-and-round 1/8" cord when I built the conduit.
7. Buy or borrow a Kellem grip and get a lot of lubricant when you pull
additional lines through the conduit. You will be happy that you made the
lines
slippery and that you had something that really grip the end of the line
tightly.
I hope at least one of those ideas turns out to be useful for you.
73, Tod, K0TO
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