I want to expand my network and transmit it wired through my home and office (in another floor). I know the IT part kind of well, but don't know how to push the network cable through a conduit (already know where's the entry and exit). Do you need a special tool for this?

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    How big is the conduit? Is there anything else in it? If so what?
    – Tyson
    Commented Apr 19, 2017 at 22:14
  • 15
    Look up "fish tape". This is a tool used by electricians to find a path through a wall or confined space, not a product used for temporary repair of a broken fish. Commented Apr 19, 2017 at 22:32
  • @Tyson half an inch, nothing else inside. Commented Apr 19, 2017 at 22:37
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    Fish tape is the answer. It is solid, so you push it through, then connect the wire and pull it back through.
    – SDsolar
    Commented Apr 20, 2017 at 3:23
  • As @Tyson described knowing what is in the conduit is a good idea. You don't want to fill the conduit with too many cables. Additionally, you might experience a lot noise that will decrease your throughput, if something like CAT5/6, and it runs parallel to electrical cable.
    – RomaH
    Commented Apr 20, 2017 at 21:03

6 Answers 6


You don't push, you pull. If you have an assistant, they can push while you pull.

Rather than waste money on a fish-tape for a job with conduit in place, just connect a vacuum cleaner to one end and feed string from the other end. You can tie a bit of plastic bag to the end of the string to make it vacuum in better, but a bare string will work for short runs.

Check at the vacuum cleaner end and stop when the string is there. If you need more of a pull, use the string to pull in a rope - either way, attach to the cable and pull it through. Braided hollow poly rope is good, but if the pull is not unreasonable a strong string will work. Tie in and tape on well, keeping it smooth.

I have done this rather a lot. The only place I want fish tapes is if I'm trying to hook two of them in a wall without conduit that I can't just rip open for access. Pulling tape is more useful, but likely overkill for a job in your house (it's a flat, flexible tape somewhere between string and rope, often marked so you can measure distance with it, too.)

In most cases if a conduit has other wires in it, you will be better off pulling those out (use them to pull in a rope) adding the new cable, and pulling all of them in at once - adding a cable is considerably more difficult with other cables in place.

  • Seen the vaccuuming on youtube. You can probably use any string but I went with the Klein pull line because it was easy to work with in the canister. homedepot.com/p/Klein-Tools-500-ft-Pulling-Line-56108/100660158 This is a good video on tying the string to the cables.youtube.com/watch?v=9kK4IugMIn0 Commented Apr 20, 2017 at 3:20
  • This simple cheap solution seems great here. According to OP he's lucky enough to have empty conduit, it's also small. In this case it shouldn't require much equipment or effort.
    – JMac
    Commented Apr 20, 2017 at 12:21
  • If it's particularly difficult to vacuum the string, try partially filling the plastic bag with something light and malleable. A bit of old insulation usually works pretty well. Commented Apr 20, 2017 at 15:07
  • Related: diy.stackexchange.com/questions/100279/… Commented Apr 20, 2017 at 16:21
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    I've used the vacuum method with great success pulling wires through buried conduit with nearly 360° worth of bends in it. Not even the fiberglass fish tape would make it through the bends. Commented Apr 20, 2017 at 16:21

Depends on how bendy the path is, what's in the conduit already, and where any intermediate access points may be. In an empty conduit I can usually push wire around one 90. More than that gets difficult.

I have been known to pull and push the existing wires a couple inches, using the "push" motion to drag the new wires through inch by inch.

The first and most obvious tool is a "fishing tape", a stiff spring-steel wire with a hook on it. It's designed to be pushed through conduit containing existing wires. Then you hook and tape your wires to it, wrap this splice with enough electrical tape that it won't snag on anything, and pull the wires through. That's why they call this craft "pulling".

There is indeed a whole electrician's truck full of pulling tools - lube, "Chinese finger puzzle" wire grabbers, even power winches. The biggest mistake we often see from DIYers is using the smallest (cheapest) conduit that is legal for his/her wires, and maximum allowed bends... And then needing to call that truck because they've made the pull so difficult.

  • and in reality Ethernet through a conduit in the wall makes me think he is trying to go through an Electrical Power AC conduit line. Which with Ethernet is a bad idea - AC induced in the Ethernet is not helpful for the Ethernet.
    – Ken
    Commented Apr 21, 2017 at 18:13

Purchase a fish tape.

You can find them at any building center. Ensure it is flexible. Push the fish till it comes out the required end, tape the cable on the end, and pull.


The vacuum cleaner trick is already mentioned, excellent! But if you don't have the string, chances are you might have an old (audio) cassette lying around instead. You can take it apart and use the tape. You know the rest!


If you do not have a fish tape and do not want to purchase one for a one time use start by tying a small piece of tissue to a string. Place the tissue into one end of the conduit. Use your vacuum to suck the string through the conduit from the other end.

  • 3
    Isn’t that what Ecnerwal said?
    – JDługosz
    Commented Apr 21, 2017 at 5:21

If it's a VERY short distance between the entry and exit, try a straightened-out length of coat hanger, some duct tape, and the end of your cable.

Fish tape is useful, as the others have stated. I wired a whole 3-bedroom apartment myself once, mostly from the attic. For some of the locations, I was running more than one cable (sometimes up to three) through drilled holes. Instead of using the fishtape multiple times (which becomes more difficult) through the same hole, I'd fish a length of nylon "parachute" cord through a hole, and then duct-tape my wires to the parachute cord at staggered interviews to keep the profile as flat as possible. Then I'd go back to the hole and PULL the parachute cord through.

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