Help with a problem

[jm1470]

Ive been working on a job with a fire alarm company, bringing electric to there panels. The job is at a residence inn in south jersey and they have 28 buildings that they are upgrading the fire alarm system. Here is the problem all of these buildings are connected though underground piping system. They ask me to pull in rope so that they can run there cable in to network all of the fire alarm panels together. I've manage to map out the pipes and been able to pull a couple of ropes in. Some of the pipes are just being stubborn I tried putting a snake in, but have to be careful cause there are already other wires in the pipes, including phone and the old fire alarm wires, that are still being use. I've try to hook a vacuum up and try a bag to the rope to no avail, I've tried sucking all of the water out of pipe and even blowing compress air though the pipes. Does anyone know of another way to get a rope in the pipes there is about 200 feet of pipe between buildings.
thanks

 

[Dennis Alwon]

I don't believe there is a safe way to do that. I would try and pull out all the conductors and pull a pull line in as I pull the others out. It is very easy to damage the other wires or cables in the pipe if you try and pull another one in with them left in place.

 

[480sparky]

Use the existing cable(s) to pull in a rope and replacement cable(s).

 

[hurk27]

I have had similar problem with trying to get new conductors in raceways after the fact, I found that if all the conductors we installed in one pull they tend to turn as they are being pulled in so no you have all the conductors wrapped around like a big bundle, almost imposable to pull a wire out to pull a couple wires in (or rope) and this is even on short runs let alone on a 200' run.
Add that to the possibility of rust and sediment in the pipe, and you have one tough pull.

not trying to discourage you but trying to let you know what your up against to make a better choice on how to tackle this job.

Now with the bad news out of the way we can look at the possibility's that the conductors were installed one at a time or in groups (most likely)

If you pull on a conductor and a few other conductors seem to want to move with it, this is probably a group of conductors installed together, and can be even taped in a bundle, keep tugging on each of the conductors and see if you can find one that will move independent of the others, have a person at the other end to make sure it moves the whole run, then pick this wire as you pull out wire to pull in a replacement conductor and a pull string or to pull your pull rope in.

The other option is using the correct fish tape for the size of pipe.

If the pipe is over 1 1/4" and there seems to be room, try to find a 1/4" or 3/8" fish tape, they make a end to go on it that looks like a bullet, and attach?s by two set screws, these will push into a pipe and push farther then a 1/8" fish tape, I have a 300' one that is great for long runs, they just don't like allot of turns as they tend to like to bend in one direction.

Pulling in more conductors in existing pipe is one of the more challenging jobs in old work, but with the right tools and equipment it can be done.

 

[ceb58]

I know you said you tried a vacuum with a rope,but the rope may be too heavy. Give it a try with a bag and mason twine. I have found it sucks easier than a jet line. Then use it to pull in a rope.

 

[Dom99]

Don't know if this will help but if you check out the October 2010 Electrical Contacter magazine page 56 titled 'Ideas that Work" you'll see a picture of a pull string attached to a plastic soft drink bottle which will ride on the surface of the other wires.

Depending on your conduit size you may have to use a smaller plastic bottle. Run a piece of pull string through the bottle and tape it well to attach the cables and fish tape etc.

 

[wireguru]

you need to use the right tool for the job. I dont think you would ever get a fishtape through that. I would also be worried about trying to vac a soda bottle through an occupied conduit, you would have a real mess if that got stuck and broke. You need a conduit rodder which is a large reel with XXX feet of 3/16 or 1/4" solid fiberglas rod. That will push past wherever the wires are twisted or bundled. See here (no affiliation with this site) for an example http://www.wctproducts.com/rodder_page.htm here is another http://www.innerduct.com/products/duct_rodder.php

also think about the damage the FA contractors pulling on the rope you install could cause to the existing conductors. Perhaps it would be better to install mule tape than rope.

How much room do you have in the conduit? Do you have room to get an innerduct (there are some small ones 3/4" inch or something IIRC) in? Maybe you could get a rod through the conduit, and use the appropriate fittings on the end of it to pull an innerduct in (primarily pushing and tons of lube).

im no expert in UG work, but figured these thoughts may help