A knock out plug is a hole that has a cover over it. You will usually need to use a screw driver and a hammer to “knock out” the cover. Check out this picture…. Once you knock out the plug, be sure to remove the plug because it may clog the drain if you leave it in there.

What is a knockout on a garbage disposal?

Knockout plugs are often used to connect dishwashers to garbage disposals. … When the dishwasher drains down, it can push water into the disposal through this tube. Since not all homes have a dishwasher, disposals with this feature will typically have the opening blocked off by a knockout plug.

How do you remove knockout from inside electrical box?

Knock out removal If you can only access a knock out from the inside of the box, drive a self tapping sheet metal screw into the knock out and use your lineman pliers to wiggle the screw back-and-forth to remove the knockout.