How to Seal Cutouts in Electrical Boxes

Written by thomas mcmurchie
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to Seal Cutouts in Electrical Boxes
Open cutouts in electrical boxes must be sealed. (PM Images/Digital Vision/Getty Images)

When finishing work on electrical junction boxes it is important to close all holes in the boxes. Cable connectors are used on the entrance and exit holes for the cable. The connectors protect the cable from being accidentally cut by the edge of the hole. If another hole has been mistakenly popped out it should be covered. These open holes could be fire hazards. Home improvement stores have the necessary equipment to complete this task.

Skill level:

Other People Are Reading

Things you need

  • Screwdriver
  • Cable connectors
  • Metal snap-on hole covers
  • Hammer

Show MoreHide


  1. 1

    Be sure the power to the electrical box that is being worked on has been turned off. This is done at the fuse box or circuit breaker panel. Remove the cover or faceplate from the junction box. When running cable through a knockout hole, use the cable connector. Unscrew the locknut on the connector. Slip the connector over the cable end. Thread the cable through the knockout. Tighten the screws on the connector until it is snug against the cable. Slide the locknut up the cable and thread it onto the connector. Use a screwdriver to tighten it securely.

  2. 2

    Place the snap-on hole cover over any open and unused knockout holes. Gently tap into place with the hammer.

  3. 3

    Replace the cover or faceplate to the junction box. Turn the power back on to the circuit on which you were working.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.