Finishing Your Basement

How To Build And Use A Cable "Mouse" To Run Wiring Through A Flexible PVC Conduit

Using flexible PVC conduit to route electrical wiring to landscape lighting, sprinkler controls or other low-voltage applications is smart and simple. It's not only an affordable means of burying wiring, bu it also provides protection from corrosion and accidental damage. However, it can be tricky routing wiring through long stretches of flexible conduit, especially if the wire is thin. That's why using a cable "mouse" will help make the job much faster and less tedious. Below are the materials you will need and how to set up the mouse and run the wiring:

What you will need

  • Shop vacuum with hose
  • Duct tape
  • Balsa fishing float
  • Fine-grit sandpaper
  • Braided nylon twin

Step-by-step procedure

1. Purchase your materials - You will be able to find a couple of the items--fishing float and nylon twine--on the fishing aisle of a general retail store or sporting goods store. The other items should also be available at any general merchandise store.

When selecting your float, look for a cylindrical balsa float with a stem on at least one end. These floats are sometimes labeled as slip bobbers or spring bobbers. Avoid ball-shaped floats, as the "torpedo" shaped floats will slide more smoothly through the conduit.

The next important step when choosing a float is to purchase one that is at least the same diameter as the inside diameter of the conduit. Bringing a sample piece of the conduit to the store will help make matching the float and conduit a simpler task.

If you aren't able to locate an exact fit, then purchase the next larger size; you can sand around the circumference of the float with fine-grit sandpaper until it fits inside the conduit. The float should freely move inside the conduit, but the gap between the float and conduit wall should be minimal for best results.

The next critical item to buy is braided nylon twine. Twine suitable for use when hanging trot lines or working with nets is ideal for the job. Nylon is a slippery, break-resistant material and can easily handle the strain of pulling wires through the conduit. Since braided twine comes in a variety of sizes, find a diameter that is small as possible with a breaking strength of 300 pounds.

2. Set up the operation - Once you have the float and twine, as well as the other items in hand, you are ready to get everything together. Begin by taping the end of the shop vacuum hose to one end of the conduit; use duct tape to make the connection and seal it airtight.

At the other end of the conduit, tape one end of the twine to the longest stem on the fishing float with duct tape to make your cable "mouse". Be sure there are no loose flaps of tape that might catch on the conduit's interior wall. Next, unroll the twine to a straight line distance equal to or greater than the total distance of the conduit. Allow the twine to naturally untwist to prevent kinks from developing during the process of running the line.

3. Run the cable "mouse" through the conduit - After you have made all the necessary preparations, turn on the power to the shop vacuum and allow it to run for five minutes uninterrupted. This will draw air through the conduit and remove all moisture from its interior; any residual water might "grab" the float as it passes.

After the interior of the conduit has dried, carefully insert the "mouse" into the open end of the conduit. The suction of the shop vacuum will pull the "mouse" through the conduit and draw along the twine behind it. Be sure to keep clear of the twine as it pulls to prevent snags. If everything works as it should, the "mouse" will emerge at the other end of the conduit. Should it not, pull the "mouse" back to the open end of the conduit and repeat the process as needed until it finally travels through completely.

4. Run the wiring through the conduit - The last step in the process of running the wire is to tie the wire end to the free end of the braided twine; use a square knot to attach the wire and add three or four turns of duct tape to securely fasten the twine and wire. Next, gently pull on the opposite end of the twine where the float is attached and draw the wire through the conduit. Work slowly and carefully to prevent the wire from kinking inside the conduit.

If you feel you can't do this or don't want to buy supplies, you can contact a local electrician, or visit websites like, who can assist you with wiring.