Fishing cable through conduit - HELP!!!!

[Chris D]

I'm hoping somebody here can help me with an idea.

My house has a centralized equipment room in the lower level, distributed throughout the whole house. Therefore, for the two most important A/V zones, the theater and the living room, there is an in-wall conduit for each from the equipment room to the zone room. I think it's 1.5" conduit or so, and each of the conduits is estimated a little more than 50' long. Problem is, those that built the house didn't leave any runner ropes in the conduit to pull through.

I've already tried the technique of tying a washer at the end of a string and "sucking" it through from the other end with a vacuum. Problem is, this is flexible metal conduit, and I think the low pressure suction is letting ambient pressure air to come in through the little ribbing gaps along the entire length, that allow it to flex and bend. So I'm getting very low suction at the other end, and it's not sufficient to pull the string and washer through.

I've also tried using three different types of push rods--one metal wire, one nylon wire, and one a flat metal rod. For each of these, they go so far into the conduit, then hit what is probably a bend somewhere down the line and stop. (I've tried jiggling and conjoling it to go through... no joy)

The conduit to the theater already had a Cat 5 cable running through it that carries an IR signal to my projector. So, I tied a string to the end and pulled the Cat 5 cable out, for the string to be a new runner rope. Problem is, when I pulled the string back through, pulling the Cat 5 and a new runner string, it broke under tension, and I couldn't reach inside the conduit and get it. So I need to use a stronger runner string/rope, but now I have a conduit that I need to run cable through, that doesn't even have the cable that it HAD in it last week!

:M :M :M :M :M :M :M

So, any suggestions, guys, if how to make this happen? How do I get cable through a 50-60' conduit like this? (Basically need to run Cat 5 or Cat 6 cables through... eventually I'll be running HDMI video through them, extended by Cat 6 cables)

[Lex]

Chris, I am not sure what you have tried using as a feeder, but have you tried a solid wire of some kind that is SMALL diameter? If you can get anything through, it's probably going to be something like that, or a single piece of coax maybe. I Believe you have an uphill battle with pre-existing wires already in there.

The problem is the length I fear. This is a long way to push anything.

[Bent]

Chris, I once had exceptional luck using forced air from a compressor and blow-nozzle to feed a string (waxed barbours twine, actually) to pull tail-light wire through a long run of condiut.
As the air fed the string in, it would pile up, create resistance, and then plow further on it's own. Maybe this would work where suction won't.

[Paul H]

Tie a small piece of rag to the line rather than the washer - the vacuum will pull it through much better than a washer.

Alternately, get (beg/borrow/buy) a proper electrical fish tape, which will feed through the conduit.

Paul

[Kevin D]

I concur, the vacuum and string trick works but you need something a little less dense then a washer. Like Paul said, some form of rag should work. I've had excellent luck on job sites with the orange vinyl safety banners.

Use a really light-weight string and about 1-2' of the vinyl. Use that string to pull a bigger string (rope) through. When fishing the final run of wires through, have someone to help push from the other side. It will help make some impossible pulls possible.

Kevin D.

[Lex]

I saw a thing on This old house once where they used a parachute type deal to pull a wire through ductwork, but then they have a lot more room in ductwork than in conduit. This was cool to watch, it was so they could run wires for individual rooms and vent dampers, was a cool system. anyway, not relevent here. Then needed air control to each vent, so they could blow up bladders to block vents in a system designed to only heat and cool what you needed. anyway... off subject.

My last suggestion would be tie a string to a mouses tail, then put cheese at the other end, and use the fan to blow cheese air toward said mouse. Mouse runs through conduit to cheese to awaiting trap at other end, string captured, mouse killed.

[krips]

finally something im qualified to answer! a few options, some have already been mentioned
1. vaccum string , possibly use to pull in larger string or #12 rw90 etc
2. fish tape
3. use present wire as pullwire and repull it in with the new one

for tough pulls (sounds like youre using flex which sucks) we use a product called yellow77, which is a lubricant / grease . works wonderfully

hth.

k.

[Glen B]

Second the Ideal Yellow 77 wire pulling lube. That's what I use for pulling wire through EMT and Greenfield.

[Bent]

my reasoning for the compressed air was Chris was losing vacuum through the corrugations of the armour - positive pressure might just do the trick where vacuum won't

is the majority of the run vertical? If so, try to use gravity to your advantage.
a real electrical fish tape might be your best bet indeed.

Yellow 77 (or cable jizz, as I call it) will help once you finally get to the point where you can execute a good pull. I'd plan on a two stage pull, get some lighter twine or string pulled through first, then switch to something heavier such as what we call "mule tape", which is cheap, super light, and good for over 1000 pounds of tension. The mule tape will deliver the cable next.

If there are more than the equivalent of 4 - 90° bends you will be completely out of luck, all your effort will be spent in "tightening the loop", rather than pulling the cable through.

[Alaric]

Chris, I once had exceptional luck using forced air from a compressor and blow-nozzle to feed a string (waxed barbours twine, actually) to pull tail-light wire through a long run of condiut.
As the air fed the string in, it would pile up, create resistance, and then plow further on it's own. Maybe this would work where suction won't.

Bingo! I use compressed air to blow twine through handlebars to run wiring.It works. :T

[ewsea]

?balloon

how about tying a loose balloon (do not inflate) to the start of the cable, and using a vacuum to pull? the loose balloon will flap and create flexible resistance (i think that it works better than a fixed resistance). at the other end, gently jostle and push the cable as the vacuum pulls the start end of the cable.