Pulling a THNN wire in is common for a pull wire, because of the slickness
of the jacket and the availability of the product on construction sites.
The soft copper wire lacks the strength to do too much, and unfortunately it
has a fixed lay or coil to it. Pulled off a small spool, it will have a
coil to it that will tend to wrap around other cables in the same duct.
Remember the goal to having a 'pull string' in the conduit with existing
products is to have a 'path' that doesn't wrap around the existing in place
products. Throwing an extra ungrounded wire in a duct with RF cabling isn't
particularly good. It WILL be resonant at some point, so bond it to the
ground system. Much like using pieces of wire (ungrounded) to secure your
cables to the tower, they WILL resonate at some frequency and likely not to
your benefit. There are products designed for this use (UV resistant cable
ties, cable grommets, clamps, etc.) which will provide a better solution.
Yellow 77 was a popular wire lubricant, hopefully you can't find it anymore.
It is a waxed based product, and while greasy when it comes out of the
container it sets up to a hard wax finish and makes adding cables later very
tough. The newer products are water soluble, and do not harden in the
conduit.
There are so many variables to be considered. Most of the kellum grip
solutions require unterminated cables. Often, we have cables to pull with
fittings already on one end that go through the pipe and come out then get
hooked up. I've pulled coax with fittings, I've even pulled fiber optics
with delicate fittings already installed. One just has to take care to wrap
and pad all the stuff on the end before pulling.
> I must agree this (the kellum grips) are the best way to pull cable
> in
> coundit. I have pulled four high voltage lines thru a duct at the same
> time using four grips (three phase) . As one person stated, we pulled
> a
> "12 THHN thru at the same time for later use to pull in a rope to pull
> in
> another run. At least I no longer do it as am now retired industral
> electrician. For the lub we used a product called "yellow 77".
> -Jake-
> K5WTA
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