Pulling Cable in Conduit
 

I am getting close to pulling some cable through a 1 1/4 inch PVC
conduit that runs about 20 feet from the third floor attic to the
basement. The contractor claims the conduit is a "straight shot" with
no bends. I have three LMR240 cables with PL259 connectors on each
end. And I would also like to pull a 450 ohm length of ladder line.
(Measures about 1 inch.) And I would like to pull at least two 16 gage
insulated control wires.

Any advice would be appreciated.

Thanks, jimbo

Pulling Cable in Conduit
 

"jimbo" wrote in message
. ..
I am getting close to pulling some cable through a 1 1/4 inch PVC conduit
that runs about 20 feet from the third floor attic to the basement. The
contractor claims the conduit is a "straight shot" with no bends. I have
three LMR240 cables with PL259 connectors on each end. And I would also
like to pull a 450 ohm length of ladder line. (Measures about 1 inch.) And
I would like to pull at least two 16 gage insulated control wires.

Any advice would be appreciated.

Thanks, jimbo


A Google search should get you the electrical handbooks and codes (e.g.
NEC ) for the maximum fill for each conduit size. As a rough rule NEVER
fill a conduit more than 70% to 75%.

gb

Pulling Cable in Conduit
 

"gb" wrote in message
...
"jimbo" wrote in message
. ..
I am getting close to pulling some cable through a 1 1/4 inch PVC conduit
that runs about 20 feet from the third floor attic to the basement. The
contractor claims the conduit is a "straight shot" with no bends. I have
three LMR240 cables with PL259 connectors on each end. And I would also
like to pull a 450 ohm length of ladder line. (Measures about 1 inch.)
And
I would like to pull at least two 16 gage insulated control wires.

Any advice would be appreciated.

Thanks, jimbo


A Google search should get you the electrical handbooks and codes (e.g.
NEC ) for the maximum fill for each conduit size. As a rough rule NEVER
fill a conduit more than 70% to 75%.


The NEC is mostly for wires for the AC lines. It will not apply for the
antenna wires.

The ladder line is not going to work too well in the conduit with the other
wire. There is a minimum distance that it should be placed from other
conductors.

Pulling Cable in Conduit
 

jimbo wrote:
I am getting close to pulling some cable through a 1 1/4 inch PVC
conduit that runs about 20 feet from the third floor attic to the
basement. The contractor claims the conduit is a "straight shot" with no
bends. I have three LMR240 cables with PL259 connectors on each end. And
I would also like to pull a 450 ohm length of ladder line. (Measures
about 1 inch.) And I would like to pull at least two 16 gage insulated
control wires.

I specified a similar PVC conduit when our home was built. I simply
"dropped" the cables down the conduit from the attic, and let gravity do
all the work. If you drop them all down together at the same time you
should have no problems. The LMR240 and control wires will be fine, but
ladder line in the same conduit with all those other wires probably
won't work very well.

73, John NU3E

Pulling Cable in Conduit
 

Pulling Cable in Conduit
 

I am getting close to pulling some cable through a 1 1/4 inch PVC
conduit that runs about 20 feet from the third floor attic to the
basement. The contractor claims the conduit is a "straight shot" with
no bends. I have three LMR240 cables with PL259 connectors on each
end. And I would also like to pull a 450 ohm length of ladder line.
(Measures about 1 inch.) And I would like to pull at least two 16 gage
insulated control wires.

Any advice would be appreciated.



I think you can get those three coax lines down the straight conduit
if you stagger the PL-259 connectors, however, once you have a couple
cables in the conduit, you may find there isn't enough room for a PL-259
to squeeze by, so you may need to remove the connectors, pull the cables
and then reinstall them. Three LMR240s and two control cables are going
to fill that conduit more than you realize!

As far as the Ladder line goes, DON'T ! It will be nearly useless
packed in with all that coax and wire as it needs several inches of
SPACE around it to function properly, with no nearby metal objects. That
coax braid in close proximity will drastically reduce its effectiveness.


Ed K7AAT

Pulling Cable in Conduit
 

Yes a very negative effect and not a good idea.. If you look in the
history of this NG you will see some numbers about minimum separation
distance from other metal.

If you really want to run a balanced feeder you can use two pieces of
coax with the shields connected at each end. The Z will be twice that of
the original coax. (I use this as a Q section on 20m feeding a loop of
about 170 ohms) Dunno about losses in this case (which open wire feeder
are great for reducing) and of course the Z is going to be kind of lower
than 450r.

Cheers Bob VK2YQA

jimbo wrote:


Thanks for the replies. The ladder line would be used when the other
lines were not being used. Does the proximity of other unpowered lines
affect the ladder line operation for receive and transmit?

Thanks, jimbo

Pulling Cable in Conduit
 

Jimbo,

It's going to be crowded in that conduit, so don't rely upon gravity to get
that stuff down the pipe. Three suggestions:

1. Buy a 25 foot electrician's steel snake (Home Depot, Lowe's, ...), use
this to pull the wires through; or drop a length of poly line/guy string as
a pull line. If gravity does not get the pull string through the conduit,
tie a lightweight object to the line and suck/pull with a leaf blower or
vacuum cleaner.

2. Stagger the pl-259's and open cable ends as much as possible so that this
looks like a pointed, rather than a blunt, object going through the conduit.

3. When you're pulling the wires into the conduit, do your best at the feed
point to keep the wires "straight" and not twisting into the conduit. This
takes less space and permits you to do item #4 .

3. ADD A PULL STRING IN THE CONDUIT WITH THE WIRES! So when you're all done,
three months from now, and you realize you just want to add one more little
4 conductor cable (or whatever!), you can do it without completely
dismantling the cables. {been there, done that}

--
-larry
K8UT
"jimbo" wrote in message
. ..
I am getting close to pulling some cable through a 1 1/4 inch PVC conduit
that runs about 20 feet from the third floor attic to the basement. The
contractor claims the conduit is a "straight shot" with no bends. I have
three LMR240 cables with PL259 connectors on each end. And I would also
like to pull a 450 ohm length of ladder line. (Measures about 1 inch.) And
I would like to pull at least two 16 gage insulated control wires.

Any advice would be appreciated.

Thanks, jimbo

Pulling Cable in Conduit
 

jimbo wrote:
Thanks for the replies. The ladder line would be used when the other
lines were not being used. Does the proximity of other unpowered lines
affect the ladder line operation for receive and transmit?

Especially transmit. You will lose a lot of your transmitted
power to the conductors surrounding the ladder-line. Ladder-
line should be run a few inches away from anything.
--
73, Cecil http://www.qsl.net/w5dxp

Pulling Cable in Conduit
 

On Sun, 22 Jan 2006 08:29:29 -0700, jimbo wrote:

I am getting close to pulling some cable through a 1 1/4 inch PVC
conduit that runs about 20 feet from the third floor attic to the
basement. The contractor claims the conduit is a "straight shot" with
no bends. I have three LMR240 cables with PL259 connectors on each
end. And I would also like to pull a 450 ohm length of ladder line.
(Measures about 1 inch.) And I would like to pull at least two 16 gage
insulated control wires.

Any advice would be appreciated.

Forget the ladder line! It will be a disaster.





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