How to seal electrical boxes

Written by brad chacos
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How to seal electrical boxes
Sealing around electrical boxes protects against the elements. (Jupiterimages/Comstock/Getty Images)

Electrical boxes and outlets provide much needed electricity to homeowners, but they also provide an unwanted path for air to leak out of or into a home. Regardless of whether its cooled air or heated air blowing out, or strong drafts of outside air blowing in, air leaks in a home can wreak havoc both on the temperature inside your home as well as your utility bills. This is sometimes because the one area that homeowners often forget to seal is the area around outer-wall electrical boxes.

Skill level:
Moderately Easy

Things you need

  • Rag
  • Flathead screwdriver
  • Fire-rated silicone caulk
  • Sandpaper (optional)

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  1. 1

    Switch off power to the electrical box at the main circuit breaker for the building.

  2. 2

    Clean the area around the electrical box. Lightly dampen a rag and wipe around the outer edge of the box. Work the rag into any gaps between the box and the surrounding drywall. Dry the area once it's cleaned.

  3. 3

    Load a caulking gun with fire-rated silicone caulking. Seal the space between the electrical box and the surrounding drywall, pointing the tip of the nozzle into the crack at a 45-degree angle. Move the nozzle along the crack around the box, sealing the gap in one smooth, continuous motion.

  4. 4

    Remove the electrical box's faceplate. Use a flathead screwdriver to open most electrical boxes. Seal any holes in the body of the electrical box, including the hole the wires travel through.

  5. 5

    Allow the caulking to dry, then replace the electrical box's faceplate. Sand down any excess caulk as necessary, using a fine-grit sandpaper. Restore power to the electrical box.

Tips and warnings

  • Gaskets or special airtight electrical boxes can also be used to seal electrical boxes.

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