I just closed up a project today that requires 1000 feet of conduit to be pulled about 1000 feet. The conduit is 4 inch but without pull string. What would be the best method of getting that through the conduit? I doubt sucking a string through would work at that distance.

Get a ball of foil, wrap it lightly just slightly smaller then the diameter of the pipe, as you wrap the foil into the ball interwrap fishingline or masons string, place your shop vac on the other end of the pipe make sure its sealed and turn her on, within a minute you will have your string, the go back to the other end and tie on your pull rope to the masons string or fishing line and pull that. Your Done!!

try and get a helper on the other end to make sure the string doesnt get tangled :)

If the shop vac isn't strong enough (balled up plastic bag may work too), maybe a leaf blower?

Any 'Cees' or pull boxes/fittings along that run? Maybe that you haven't found?

Maybe you can rent a 1000' fish tape, or rod, or maybe a high CFM compressor.

[Link: platt.com]

If you have a decent shop vac then it should pull through just fine, pipe size doesn't really matter as long as there is enough suction and minimal air loss around the mouse or rag being pulled through the pipe and it doesn't weigh too much.
You can also rent one from a place like

[Link: thompsonsrental.com]

Plastic bags work well as they form out to the size of the pipe once they're sucked inside the pipe.

You want suction so that the string can be pulled into the end that doesn't have your air source/suck attached to it. You can get higher pressures by pushing air than by pulling, but then you'd have to work out how to seal the air blower onto the same end of the conduit that is open enough to let the string go in.

However:
You have 1000 feet of conduit. You don't mention the type of connectors used on these conduits, but if each one leaks a little bit of air... and you have 99 of them... maybe you won't get much pull, maybe you can't pull in a ball. And why wasn't a rope run in along with the conduit? This sounds like something done for the first time by whoever did this, and I hope it's not one of those PITA "learning experiences."

And who the hell approved this? You're describing a pull that might be illegal in some places because it has no pull boxes along the way and will use up exactly the amount of wire contained on the usual spool. Sorry, but I smell trouble here.

You don't say it's a straight pull, you don't say there are any bends, so we can't add anything there; as always, the idea behind giving the model number in this case would be "describe the thing fully." If there is one bend in it, you're in trouble. If there's two bends, you will be pulling the conduit apart before the run is finished. If there are three bends, I suggest you declare that, in your judgment, this pull cannot be done without adding one to ten pull boxes (and those are still far apart) and adding billable time to make it work. After all, if you did not design the run, then you are only responsible for pulling wire in if it can be pulled in. If it can't be pulled in, then you charge to make it work. Anything extra needed to pull it in is a design change, change order, and you must charge for what it takes.

By the way, what's the fill percentage? We had to open up a 1" conduit with four bends in it on a 65 foot run with about 20% fill. Yours might be worse!

The electricians installed all of the conduit and the client wasn't able to tell me if there were boxes along the way. It's a straight run with no bends

Hmmm...thought that distance wouldn't have the suction but hey, I'll give it a try!! Thanks

Another couple of good ideas.....thanks

that's a crazy long ass run of conduit for no service boxes in-between. 

It should have suction. I would imagine there will be a couple of boxes in that run though.

If the electricians were licensed, I'd hope they did it to code with the proper pull boxes installed as if they had to use the conduit themselves.
I'd talk to the electrician to have him explain the conduit run, etc. before you commit to anything.

One would hope so! We were on a residential job last year that had several 4-6" conduit coming from the central plant to a lower level IDF; nearly 2000 feet and not a single junction box! There were pull strings but they weren't budging...conduit needed to be auger'd out, flushed clean, then jet line used. Thanks d1cks!

Gman You never mentioned how the conduit is installed. Metal EMT exposed?
PVC encased in concrete? Coreline? If it is incased in concrete and the run is infact straight; you should be able to suck in a string without a problem. The bag trick does work.

Any job I've been on the electricians would put a string in for you?
We typically would use a greenlee and suck string into all the conduits. Most jobs I've seen usually spec that the conduit installer supply a pull string fot the sub- trades. It is done to ensure the conduit run is done correctly and is ready to pull cable into. What scabby electrical contractor doesn't install a pull string?

Just did one where the electrican used 1/2" conduit for two 14/4 speaker wires. About 160 feet no boxes and three 90's and no pull string. I tried the vacuum, 250 conduit tape, and neither worked. I could get through two of the 90's and could get it past the last 90 going either way. The contractor screwed a fitting onto a 1/2 inch conduit cap and connected it to his 40 gallon compressor. Got it through the last 90 with the compressor and the vacuum. We put a piece of sponge on a pulls strong. Good luck!

Mike

Make a sail out of the right sized [ziplock] parts bag. Cut drinking straw the right length to hold bag open and thread string through. Suck through with very large shopvac or if thats not enough power make a small notch on one end of the conduit for string to slip through and blow it forward with a leaf blower. It should work because your sail is light but has plenty of drag.