Home Electrical - Pulling Wire Thru Conduit

[mookie]

With the wide range of experience here, I thought I would see if someone can help me.



I need to pull wire through a 150' long conduit. I've only seen fish tapes that are 50' long.



What's the method to pulling wire longer than 50'?



Thanks!

 

[Dale Carlson]

Get a longer fish tape? Not to be a smart ass, but they do make them longer. Maybe you could rent one?



If not, maybe put a pull box every 50' in the conduit. Fish it to the pull box, pull your cable through, and then fish it to the next one. Depending on the conduit, you might just cut it every 50', and repair the conduit when you're done pulling the wire.

 

[mookie]

The conduit is under concrete running out to my bbq.



Renting is a possiblity; I just didn't know if they made longer ones.

 

[Todd Z]

Using a vacuum, Tie a small plastic bag, or ball of plastic wrap, to a string and suck it through the conduit. Make the string 175 feet and tie it off on 1 end...



Then soap the wire as you pull it in and you should be good to go..



Todd Z

 

[mookie]

I never thought of using vacuum. That's really creative.

Have you done this before or heard of it being done?

 

[Dale Carlson]

Seems like there should have been a small pull box on the outside of your house that sits between the household wiring and the bbq. That might make the run shorter.



We have a 100' fish tape for pulling network cabling. I know our cabling contractor has some even longer.



BTW, standard methodology is to fish the tape, with some small (polyethylene) rope attached, and then use the rope to pull the wire through. It's usually better to pull TWO pieces of rope through. Tie off the second, with slack, at both ends, and leave it for future use.

 

[mookie]

Thanks for the help!

 

[Richard L]

kefguy is correct. You cannot buy a single piece of electrical conduit longer than about 20 foot long so you must have several pull boxes or conduit end connectors along the length of the pipe.



All you should need to do is pull the cable between the pull boxes, or the conduit connectors. To gain access you will need to remove the cover off the pull boxes, or unthread the couplers along the pipe and pull it in 50 ft sections or less.



To make it easier to pull you can use liquid dishwashing soap to lube the wires before you pull them through. That is especially important if there are already wires in the conduit that must remain.



..Rich

 

[Dreman]

It might be hard to get to the conduit if it's under concrete!



The vacuum idea should work. The fiber optics guys use something similar to run 500' or more at one time. One thing - DON'T GREASE THE STRING! The vacuum won't have enough suction to overcome the drag created by grease or oil. When you pull the wire through, however, grease the wire. You can pull a LOT harder than a vacuum!

 

[Todd Z]

Mookie,



I am a construction inspector, I have seen most "tricks" and "fixes" out there....



Also Electrical Code here is 200 Linear feet between pull boxes....



Todd Z

 

[Bill V]

No personal experience at this, so this definitely doesn't qualify as an "expert tip"--but if you try the vaccuum idea, I'd recommend marking off on the string the length of the conduit (assuming you know the exact length, or that you know there are no underground bends and therefore can estimate the length). Then, have someone stop the string from advancing when it should be just extending out of the conduit. Otherwise, the string and whatever else you have attached to it could get wrapped up in your vaccuum big-time!

 

[mookie]

Thanks, again, guys!

 

[Benjamin Feinstein]

It has already been said above but to save yourself some headach in the future make sure you run a pull string through with the new wire so that it is in place if you need to pull something again.

 

[Frank Marano]

if it is outside in the dirt, i would dig it up....? I dunno....

 

[Ron N]

Todd is right, depending on the size of conduit. If it larger than 3/4 inch, you can also use a ping pong ball with a hole drilled thru it and the string attached._Ron

 

[CountyMounty]

Is the conduit currently empty. If so try the vacuum idea with a ping pong ball or something similiar that is fairly light and is a just slightly smaller in diameter then the conduit. Use a very light weight string at first once as it will vacuum better, do not grease the string. Once that is through tie a couple of heavier weight pieces of pull string (in case one breaks or pulls off or whatever, phone wire works well for this if you can buy it real cheap or have some laying aroung like I did) and then connect your wire to that. You may not need to bother greasing the wire if there is ample room and it is the only wire going through. If there are other wires or any concern of it getting stuck you may want to. When you are done make sure there is a pull string left in there in case you want to run wire in the future. I would think that a good shop vac would work best. Also if the vacuum thing doesnt work or if you have access to a more powerful blower you could try that as well. The vacuum should work, it shouldn't take too much power as long as there is little leakage. Let us know if things go smoothly.

 

[Ryan Schaecher]

I've also seen people use an air compressor and blow a thin line down the conduit. However, it was on shorter runs...

 

[Ryan Schaecher]

Just an update... I was at a local eletrical supply store on Wednesday. Greenlee (and others probably) make what's called a Conduit Piston. It's the right size for the conduit that you want and you tie a string to it and can either blow or vaccum it through conduit. There is a "special" vaccume that can be used for it as well, bit a shop vac should work too...

 

[TomT]

If it's larger then 3/4" you could use the "Richard Gere method" and tie a string to a gerbil and get him to pass through the conduit.

 

[Gerald Pierce]

If it's larger then 3/4" you could use the "Richard Gere method" and tie a string to a gerbil and get him to pass through the conduit.

That is so wrong! But funny!