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.
If you want to use a source with the maximum wires already present, it may be possible to split the source before it enters the box. Cut access to the wiring through the wall material and add a junction box to splice the new outlet into the circuit. Cover the box with a blank plate to protect the splice.
A safety device used to interrupt the flow of electricity in case of a short or overloaded circuit. These can be made of glass with a threaded base for 120 volt branch circuits, or a cartridge design with a copper cap on each end for 240 volt circuits. Fuses are found mostly in older homes with small, 60 amp service panels.
A two wire cable run from a light fixture to a switch on a wall. Its only function is to control the on and off state of the light. Underground Feed cable used to run electricity underground. The sheathing on this cable is thicker and more durable than the NM cable used for interior applications.