A pipe through which an electrical cable is run to protect it from damage. Conduit is available in metal and pvc plastic. Conduit is required in places like unfinished basements where electrical wiring is exposed and therefore vulnerable to damage.
Hold the wires together so the ends match up and twist them together in a clockwise direction using lineman pliers. Make 1 or 2 turns to form a solid union being careful not to dig into the copper with the plier jaws.
Grasp the top and bottom brackets and pull the device straight out from the outlet box so you can reach the sides and back. If you will be disposing of the old device, completely remove the terminal screws. This will make it much easier to free the hooked ends of the wires.
An easier alternative to repairing the damage is to use one coat of mud and then cover the rough repair with a preformed medallion. A plastic medallion can be installed using caulk to stick it to the surface or using the fixture cover plate to hold it in place. You can also get a plaster medallion, these should be installed using setting joint compound or plaster of Paris to attach it to the ceiling. Keep pressure on the medallion to hold it in place until the mud has set.