I have a 460' run of 5'' Sched 40. 2 90 deg bends. One on each end. I had string in the pipe. Had used air compressor w/4'' emt mouse and it sailed right through. Now, a couple mos later when I am going to pull wire, my help doesnt show up. I tied mt pulling rope to the end of the string and started pulling fromt the other end. Well, I pulled my tail through. Rope was too short, which I had known, I was going to tie another rope onto it, but, too late. Now I cannot get mouse through. Used compressor again to no avail. Just bunching up the string. Used full bucket already. ANY ADVISE APPRECIATED!!
First, you need to get that wad of string out. A 1/4" snake *should* get past it...alternately, you could use a vacuum on one one end (sucking) and a vacuum (blowing) on the other end.
There is NO formula for this..trial and error/skill and luck, etc. It is a royal PITA. WHo knows what else is in there? A family of mice, rats, bottles and cans, a wad of ice, etc.
After clearing the pipe of what you know you put in it (string, rope, sweat and tears, every four letter word known to man)..you need to make SURE it's clear. Pull a 1/4" or 3/8" rope through (attached to string). Ater getting the rope out, attach a mandrel (See links at bottom) to that rope, with your actual pulling rope attached to the other end of the mandrel(properly sized). This will clear all the debris (rats nests, concrete, etc) out of the pipe.
I already pulled evrything out. The pipe is empty, except for some water. I am pulling 15kv concentric. The wire pulling itself is the easy part. I use a Greenlee super tugger with rigging. The blowing and sucking at the same time sounds good, Really good!!, just kidding, seriously that is a good idea. What did you mean by blowing a rod instaed of string?? It is underground by the way.
It's the water wieghing down the string. Using a 5" proper sized mouse might help, but with water, it will sponge up enough to also weigh it down too. Sounds like you need a 460'+ fish tape, (You can get them in 500') or wait until the water is gone....
Blow the compessor for a few hours through the conduit to help get some of the water out. (Not that it'll do much) Then put a 5" mouse on a 500' fish tape, and help the compressor by pushing it in too, is your best bet. If it gets stuck, pull it out quick, and hopefully a bunch of water will come out with it. And wrench out your mouse... You might have to do it a bunch of times to get past the water.
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You might try inflating a plastic bag to a size just larger than the pipes ID. Once inflated tie it off so that the bag is not taut i.e., you want the bag to be a little mushy. Then tie your string to that and try and vac or blow it in. Sometimes this will work when there is a partial obstruction in the pipe. It conforms to the opening at the obstruction unlike a mouse that will just jam. If the pipe is partially full of water it will conform to the "open" section and actually pass over the water laying in the bottom of the pipe. In this case it may move more slowly through the pipe as it will be pushing a wake as it goes.
I used this once in a similar situation although the run wasn't as long as yours. If there's an obstruction and it stops there you may have to play with the string a little or experiment with the inflation level.
I also use this a lot when I'm on a job and the proper size mouse comes up missing. A sandwich bag works great on smaller pipe although you'd probably want to try a small trash bag in this case. Be sure and trim off the excess plastic.
[This message has been edited by Helectric (edited 01-14-2006).]
Plastic bag works well if the conduit is partly filled with water. In this case, at 460' long, it is likely that at some point the pipe is completely submerged, unless the pipe is fairly level the entire run. If there is a low spot the pipe will fill at that point.
If that's the case, you might be able to blow some air past that point but the plastic bag may not make it past a solid slug of water any better than a mouse. Worth a try though, but next step is the rod.
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What we have done in the past with 5" pvc underground is; We used an air compressor blowing around 150 psi. We made an adaptor to seal the end of the pipe with the air compressor. this way All the air pressure is forced into the conduit. After blowing the pipe for a couple of minutes we place our " mouse" into the pipe and blow it through, there again seal off the feed end as much as possible. It's important to have as much air as possible blowing into the pipe. The trick I use for 5" is a softball. I took some old softballs and peeled the outer covering off, I ended up with a plastic ball just smaller then the inside of a 5" pvc. I place this inside a sturdy plastic bag, then tie the string to the bag real secure. I even tape it. The best part of this set up is it will not absorb water and be weighed down it will push any water along with it.