How to Install Overhead Electrical Outlets For each overhead electrical outlet you’ll need: A metal electrical box A metal box cover with a center knock-out A strain-relief cord connector ...

First, determine the size of the missing knockout hole and subtract 3/8" to figure out what size knockout plug you'll need. For example, if you have a 7/8" hole, you'll need a 1/2" knockout plug.

If you have an eyesore of an electrical box that you're tired of looking at, just know there are a few simple and budget-friendly ways to cover it up.