After prepping the wires, install the new cord plug over the extension cord wires. Now tie an Underwriter’s knot by looping the black and white wires. This prevents the cord from being pulled out of the cord plug.
We’ve all seen that happen when you grab the cord to unplug it from the wall instead of grabbing it from the cord plug itself to remove it from the outlet. Without the Underwriter’s knot, the cord relies on the cable clamp and the connection screws to hold the wires in place. Although the clamp is designed to hold the cable in place, it is not always the case.