How to Run a Conduit Through an Exterior Wall

Updated: Sep. 21, 2023

Avoid water leaks by following these tips on how to run a conduit through an exterior wall for free and easy installation.

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Hidden water leaks caused by improper cable and phone line penetrations through the siding can cause rot and mold.

Tools Required

  • 4-in-1 screwdriver
  • Caulk gun
  • Cordless drill
  • Drill bit set

Materials Required

  • Cable clamps
  • Feed-through bushing
  • Silicone caulk

As a homeowner, you willingly go to great lengths to prevent leaks from causing water damage to your home. Think about the time spent cleaning gutters, making sure windows and doors are properly sealed, checking the chimney cap and the flashing, inspecting pipes, and on and on.

It’s all worth the effort because few things can be as ruinous to a home as unseen water leaks. But there’s one potential weak spot that may have escaped your attention: that spot in your exterior of your home where cable comes into it. Whether it’s a phone line, cable television or home internet, if the cable is improperly installed, it can lead to water damage.

Fortunately, there’s a simple fix that you can do yourself to prevent water from running across the cable and into your home where it can lead to mold or other water damage.

For this helpful hack to work, it assumes that the cable has been installed properly. Ideally, the cable should run upward and then into the home.

As a reminder, cable should never run downward and directly into your house. Rainwater will cling to the cable and follow it right into your home.

If your cable was installed incorrectly, contact your service provider and voice your concerns. They should be willing to fix the problem, but if the provider refuses to do anything about it, see if you can reroute the cable in order to gain a couple of feet.

Project step-by-step (2)

Step 1

How To Run A Cable Through A WallFAMILY HANDYMAN

Start with a loop

If you’re installing new cable, loop the cable before it enters the building. The loop will help shed the water and provide extra cable to work with in case a mistake is made inside.

A properly sized feed-through bushing will allow you to drill a slightly larger hole so you can fish the cable in without damaging it. Dab silicone caulk behind the bushing before pushing it into its final resting place.

Step 2
How To Run A Cable Through A WallFAMILY HANDYMAN

Cable fittings

Use cable clamps to hold the wire in place. Always insert feed-through bushings into holes through the siding and seal them with silicone caulk.

TV and Internet signals are the only things coaxial cables should be bringing into your house, but improperly installed cables can let in water, which can lead to rot and mold. So the next time you’re trimming the bushes, take a quick look at where the cable enters the house.

Pro tip: Try to avoid splices if you can. They can weaken your signal.