I'm an ex linesman. We used to do runs of 3 conductor lead sheathed 500mcm
(about 1 inch) cables. Distances were usually 500 to 750 feet.
My thoughts on this.....
Run TWO conduits. You say that you'll not put anything else in there, but
we all know how that really goes :-).
I'd do it all in one run. No water or critters that way. It's also almost
impossible to get your pull string in when there's a break in the middle.
Especially if you decide to try to put something else in that pipe later.
(I just ran into a situation like that out here. Never did get the
additional wire into the conduit. Had to run an additional signal over the
existing wires.)
As for getting the string in. I like to put it in while I build the
conduit. Just use a wire that's about 1' longer than the conduit and slip
it into each length as it's added. It's a little bit of a pain but not bad.
Especially if you assemble the conduit above ground then drop the assembly
into the ditch once you're done gluing it together. If that's not an
option, just use your rag trick but suck the rag through rather than trying
to blow it. Then you won't have to fight with the string. Or, as others
have said, go rent a mouse and suck it through (a chunk of the right size
foam would work nicely too).
Use lots of wire lube (available at any electrical supply store).
Use help.
Use REALLY wide radius bends (sweeps instead of elbows). A hot box (or good
two burner hot plate) will heat up the conduit enough that you'd be able to
put your own bends in too. I've done this a number of times. Keep a very
wet towel around so that when you get the bend you want you can wipe down
the pipe and make it stay where you put it.
I can't see you having any real trouble with this.
marlon
----- Original Message -----
From: <KI9A@aol.com>
To: <RadioIR@charter.net>
Cc: <towertalk@contesting.com>
Sent: Saturday, July 19, 2008 3:56 PM
Subject: Re: [TowerTalk] Long cable pull
> Wow..loaded question.
>
> I am an Electrician, with a bunch of experience pulling long runs. Here
> are
> a few things to consider.
>
> 1) Do you plan on pulling this by hand? If so, get help, and use a bunch
> of
> wire lubricant.
>
> 2) I would break the run up at least once, mid way if you can. Every 100
> ft
> would be best, that way you can use a 100' fish stell to get the rope in.
> You can buy a quazite box that you can bury. That way, if you have trouble
> pulling it, the reason is obvious.
>
> 3) You can get a line in the conduit several ways. a) rent a duct rodder.
> It
> is a coil of varying length of fiberglass rod, about 3/8" diameter. b) buy
> or
> rent a "mouse" set, and use a vacuum to blow it in. Might need a second
> vac
> on the other end to suck it in at the same time. A mouse is a foam pellet
> about the inside diameter of the conduit. You attach a thin string to it,
> and
> use that to pull a heavier rope in.
>
> 73- Chuck KI9A
>
> In a message dated 7/19/2008 5:14:50 P.M. Central Daylight Time,
> RadioIR@charter.net writes:
>
> After being disappointed in the direct burial method, I am planning on
> adding some conduit to access my low band receiving antennas. I have
> one section of conduit that is 500 feet. Can I do this with one pull,
> or will I be wishing a I had added an access box and broken the pull up
> into two parts? I have never pulled a 500 ft run before. Since it is
> unlikely that I will ever want to add another cable into this conduit, I
> was planning on using 1.5 inch conduit. The run will be straight except
> for a couple of very long curves and then the curve at the exit out of
> the ground at the ends. I need to pull one run of RG6 and one run of 16
> ga landscape lightning cable for dc.
>
> Before someone suggests sending the dc down the RG6 to eliminate a
> cable, the dc resistance of 635 ft of RG6 is about 22 ohms. (It's 625
> ft total to get to the operating position.) Besides the RG6 already has
> dc controls signals on it as well as RF.
>
> Second question: What is a good method of putting the pull string in a
> conduit this long? I have put it there when building the conduit, but
> that is a pain. I have used an air compressor to blow a string tied to
> a rag thru the conduit, but never on a conduit this long. Is that
> likely to work?
>
> Jerry, K4SAV
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