7 Tips for Burying a Coax Cable Outside

Coaxial cables on a gray background.
  • 4 hours
  • Intermediate
  • 80
What You'll Need
Weatherproof electrical sealant
Shrink tubing
3/4-inch PVC pipe
Trenching tool
Warning tape

There are many factors involved in burying coax cable. There are technical considerations as well as code and safety concerns. It is critical to educate yourself in order to avoid costly mistakes and ensure that you do not experience a loss of signal.

1. Not All Coax Cables Are Direct Bury

Some coax cable is meant to be buried directly in the ground and other cables are not. If you look at the cable and find the words “direct bury” on the cable then you can go forward and bury it without a conduit. Cables that are not designed to be buried will quickly deteriorate with exposure to soil and moisture.

2. Install Conduit

If your cable does not say “direct bury” on the cable then you should not bury it without first feeding it through a waterproof conduit. A 3/4 to 1 inch PVC pipe makes an excellent conduit and can come up out of the ground using an elbow connector. Once the conduit comes up out of the ground you will want to terminate the conduit in a position facing down or sideways to prevent snow and rain from entering the pipe. You may need to add an additional elbow to accomplish this. You can also use a conduit for direct bury cable as an extra precaution.

3. Use Waterproof Coax Connectors and Sealant

Be sure that all your connectors are designated waterproof. You can also apply coax connector sealant, and even slip a weatherproof shrinking tubing as extra precautions to ensure that your connections are waterproof. Certain sealants are made specifically for cables and electronics and you should not use household sealants. Check your local hardware or electronics store for this product.

4. Call Before You Dig

Call your local utility company to come to your house and mark all the underground wires and cables. They will flag your property and use different colored landscape paint to mark the various cable types. The paint will disappear after a few showers of rain and they will also leave a rough sketch. The best part is that it is free. You will likely have a 2 to 3 days wait, though, so plan ahead.

5. Cable Depth

You should bury your cable around 18 inches deep. You should also call your city’s building code office and see if there is a municipal code that specifies the depth for buried cable. Some municipalities require a 24-inch depth.

6. Use a Trenching Shovel or Trenching Hoe

A hand trenching tool should be adequate for the needs of a homeowner. Trenching machines are dangerous and should only be used if you are experienced and if you have lots of elbow room to maneuver. Before beginning your trench you should first dig up your sod along the trench line and lay it aside for replacement after filling your trench. Cover the sod with some damp newspaper or cloth to keep it healthy and moist.

7. Use Warning Tape

After backfilling your cable trench to about 6 inches, run a length of cable warning tape through the entire length of the trench. It is printed with the words “Caution Buried Cable TV Line Below.” Finish filling your trench on top of the tape to ground level.