If no access is available from above you can work through the outlet hole to install a specially made, adjustable fan support. Using this method it can be difficult to secure the support and set the outlet box at the proper, finished level. An easier way to be sure of proper placement is to use the method here to install a wood frame. The ceiling must be cut to do this, after which the damage can be patched and/or covered with a decorative medallion.
The best way to remove the insulation without nicking the copper is to use a wire stripper. Most strippers have a set of cutters for the most common gauges. Gently twist the strippers back and forth once or twice, and pull the insulation straight off the end.
A plug-in device that will detect the wiring configuration of an electrical outlet. Through a system of lights this tester will confirm a receptacle is properly wired as well as indicate a problem with the wiring and what the problem is. This is important for polarized, grounded receptacles that can be improperly wired and still power a lamp or other simple test device.
Leave the wires bent into hooks if you will be using the terminal screws to connect the new device. If you will be using the holes in the back, cut the wires right below the hook so you will have a straight piece to insert into the holes. Strip about ½inch of insulation off the copper to make the connection.