Also called an old-work box, these are electrical boxes with built-in clamps to fasten them into finished walls. All that is needed to install one is to cut a hole the proper size in the hollow part of a wall and insert the box. These can be used in drywall, plaster or paneling. They are best suited for adding wall receptacles and switches. Because they don’t offer much support, old work boxes are not a good choice for installing a new ceiling fixture.
An outlet for tapping into an electrical circuit usually with an appliance plug. Duplex wall receptacles are the most common type, but larger appliance receptacles are also found in household electrical systems.
Fit a nail guard into each notch, covering the new wires. Drive the plates down tightly making sure they are flush and not protruding from the stud surface.
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.