How to Remove a "Knock Out" from an Electrical Box

How to Remove a "Knock Out" From an Electrical Box

When installing or replacing electrical boxes, it is often necessary to remove a “knock out” from the box. A knock out is the plastic or metal removable panel at the rear or side of the electrical box. Once removed, it provides access to the cables, conduit, or other wiring that will be connected to the box. The following steps explain how to carefully and safely remove a knock out from an electrical box:

• Before getting started, be sure to understand local electrical codes and regulations and to wear protective eyewear and gloves.
• Turn off power to the electrical box at the circuit breaker or fuse box.
• Test the box with a voltage tester to make sure there is no power in the box.
• Find the knock out you need to remove. Use a pair of flat head pliers, channel locks, or a knock out punch to remove the panel.
• Use a hammer and punch to enlarge any smaller knock out holes to the proper size.
• After the knock out has been removed, use a utility knife to smooth any rough edges and remove any remaining plastic or metal fragments.

You have now successfully removed the knock out from your electrical box. In order to complete the project, you will then need to install cables, conduit, or other wiring. Be sure to finish all connections according to local electrical codes.

Removing a Knock Out from an Electrical Box

If you need to connect a power cord or other electrical wiring to a junction or electrical box, you will first need to remove the “knock out” from the box. With a few simple tools, you can quickly and easily remove the knock out from the electrical box without causing any damage. Here is how to do it.

Instructions

1. Gather the tools you will need. For this task, you will need a hammer, a flathead screwdriver, and protective eyewear.
2. Put on the protective eyewear. Since you will be hammering, you need to make sure you protect your eyes from any painful metal shards that may become airborne.
3. Locate the “knock out” you need to remove. A knock out is a rectangular piece of metal that is attached to the junction box on one side. It will usually have slits in it to increase its flexibility.
4. Use the hammer to hit the flat edge of the screwdriver which is pressed against the knock out. Be sure to hit it several times until it is completely detached from the box.
5. Install the box-connector into the hole that the knock out was removed from. Tighten it with the screwdriver and you are done.