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Posted: Sun Dec 11, 2011 3:31 pm
by jdlessley
aclawson wrote:(the conduit is just slightly too bendy to be able to push the cable through without using tape and string and my tape was short by just a few feet to get all the way through.
This is just a piece of technical information about network cable that may help to prevent problems from arising. Network cable should not be bent at a radius less than approximately four times the diameter of the cable. It could adversely affect signal transmission performance.

Posted: Sun Dec 11, 2011 8:33 pm
by aclawson
jdlessley wrote:This is just a piece of technical information about network cable that may help to prevent problems from arising. Network cable should not be bent at a radius less than approximately four times the diameter of the cable. It could adversely affect signal transmission performance.


By "too bendy" I'm referring to some "wobble" in what would otherwise be a straight run - the jog in the conduit is just a few inches to either side, just enough to prevent me from pushing the line through. I got it to within about 10-15 feet of where it had to be and couldn't see far enough in to snag it even with my snake cam (which is only 6 feet).

Posted: Mon Dec 12, 2011 7:16 am
by Aczlan
aclawson wrote:By "too bendy" I'm referring to some "wobble" in what would otherwise be a straight run - the jog in the conduit is just a few inches to either side, just enough to prevent me from pushing the line through. I got it to within about 10-15 feet of where it had to be and couldn't see far enough in to snag it even with my snake cam (which is only 6 feet).

I would use a vacuum and a "mouse" to pull a pullstring through, then pull the cable with that.
I used that method on a 120' 4" conduit that had a 1" cable in it. About 80 feet in, the fish tape got caught on the cable and wouldn't continue (tried 4-5 times from each end). I made a "mouse" from a shopping bag with 4-5 bags inside it, tied my pullstring to that, then sucked it through with the suction side of a leaf blower.
I have also done that with a shopvac when my pullstring came off of the wire in the middle of a conduit that went from 3/4" to 1" with an pair of underground sweep 90s.
See: http://electrical.about.com/b/2011/08/22/how-do-i-pull-wire-through-conduit.htm for more details

Aaron Z

Posted: Mon Dec 12, 2011 8:19 am
by aclawson
Aczlan wrote:I would use a vacuum and a "mouse" to pull a pullstring through, then pull the cable with that.


I wanted to do that but ran into the following problems:

You can't get good pressure in the conduit (positive or negative) because it has five T junctions along the way where a vertical run goes up then elbows into the various offices. There is no conduit running through the actual cinder blocks, there is only a hole that goes through at each point but that leaves a pretty big void between the inner and outer block edges.

At the point where the conduit goes around the corner there is a 90 degree junction box - not a bend, but there is a hole coming in one side then a hole going out on another. That's how I found out about the void in the block - I ran my tape from this box back to the point of entry where it promptly took a nose dive down between the sides. A piece of cardboard wedged in there to bridge the gap fixed that problem.

Easy to fix with a longer piece of fish tape - that will get me from the corner to the first riser where I can open the junction and pull it up the foot or so and poke it through the wall, then push my tape through to the next riser which is only about 2/3 the distance from the corner (without any of the wobbles), 2 feet to the next one, then 20 feet to the next one and then another two feet to the last one. The only problem was getting from the corner to the first point of entry.

Fortunately I figured out the potential problems before they installed the 2nd run of conduit and asked them to put the string in as they went along. For the longer and more complicated run I already have pretty pull strings sticking out of the wall :)

fish tape alternate

Posted: Sun Dec 18, 2011 3:50 pm
by hcarter951
In some cases where a tape is too short or the run too bendy, a shop vac and a roll of zip line can be an alternate solution. Sounds like you got you hands full.

Howard

Posted: Mon Dec 19, 2011 6:55 am
by harddrive
hcarter951 wrote:In some cases where a tape is too short or the run too bendy, a shop vac and a roll of zip line can be an alternate solution. Sounds like you got you hands full.

Howard


It's interesting to hear these ways of pulling cable. There are a few conduits that I have seen that has taken a 250' fish to get through. I have a couple of buildings that 250' was needed, but most of the time there are junction boxes and if you can find that then you just go from junction box to junction box.

Just my 2 cents worth.

Posted: Sun Jan 15, 2012 3:21 pm
by JeffTurgeon
aclawson,

Many years back I was the YSA Rep for Westland, just after my return from my mission. I attended many YSA activities at the Bloomfield Stake Center.

I also remember that old Greek Orthodox building the church took over. Does it still have solid glass doors to the gym and those original pews with the crucifixes carved into them?

Posted: Sun Jan 15, 2012 7:21 pm
by jdlessley
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