How to Seal Electrical Outlets

Turn off the circuit breaker that supplies power to the outlet. This is an important first step, otherwise you risk getting shocked when you try to remove the faceplate.

Remove the outlet faceplate using your screwdriver. Don't remove the screws all the way, just enough to allow you to take the faceplate off. Keeping the screws in the faceplate prevents you from losing them.

Use a small brush to brush away any dust around the edges of the outlet receptacle if necessary.

Spray your insulating foam slowly and carefully between the wall and the outlet receptacle. Do not fill it too quickly or too full, as it will expand to fill the gap. Leave it to dry for about 24 hours, and when it is set, scrape away any excess sealant foam using the flat blade, so that it is flush with the wall.

Fit your foam gasket over the outlet. You can find these in most good hardware stores, and they come pre-molded to fit a variety of outlet shapes and sizes, so make sure you buy the right one. Simply place it over the outlet sockets, and it will cover over and insulate the space between the socket and the edge of the outlet receptacle.

Place your outlet faceplate back on the outlet, and screw it back in. Once you have done this, it holds the foam gasket firmly in place, and your outlet is sealed and insulated. It is now safe to turn your circuit breaker back on.