During remodeling projects, you may need to convert an existing plug-in outlet into a junction box, perhaps if you're going to build cabinets or closets in the area. You must keep the junction box cover accessible, but it's dangerous to simply leave an outlet in a place difficult to reach. Another reason you may want to convert receptacles into junction boxes is for safety in a child's room. When the child is older, you may want to reinstall the plugs.
Shut off power to the receptacle.
Use the voltage tester to determine if the power is off. Insert the tester into both outlet plugs; the receptacle could be half hot.
Remove the cover plate. Unscrew the current plug and pull out of the box as far as possible. Straighten the wires.
Unscrew the set screws to all the wires. Unhook the wires and straighten the ends. Discard the outlet.
Twist hot wires together using the pliers. Turn in a clockwise direction, and wrap at least three or four turns. Make sure you have twisted the ends of the wires.
Twist on a wire cap in a clockwise direction until it's tight. Wrap with several turns of electrical tape until you've secured the cap to the wires.
Twist the neutral wires together and cap and tape in the same manner.
Twist the ground wires together and cap and tape in the same manner.
Return the wires to the box, making sure the caps do not come loose.
Cover the junction box with a solid junction box plate.