In this example a new wall receptacle can be installed using an existing receptacle in an adjacent room. This can often be the easiest and most likely solution to access a source for a new receptacle or a switch to a new light fixture. Set the new outlet box in the same wall space as the existing one to simplify running the cable.
Pry the molding off the wall working at each stud. Drive a broad chisel-type joint knife between the baseboard and wall. Pull out on the handle several times to loosen the molding enough to wedge a crowbar behind it.
By code the junction box must remain accessible, so look for a spot where the cover plate will blend. Use a 3x2½ inch device box like the ones use for wall outlets and set it at the same level as the existing wall receptacles to minimize visual impact.
Locate the two joists nearest the new fixture location using a stud finder or tap on the wallboard until the sound indicates the general location of the joists. Use a drill and an eighth inch bit to drill through the plaster where the joists are estimated to be. Drill holes at 1" intervals until you meet resistance and wood from the joist is ejected. Mark the location of each joist with a pencil mark.
With the 2x4 and box assembled, hold them between the joists so the outlet box presses against the back of the ceiling. Trace the outline of the box with a pencil to mark the hole. Remove the assembly and cut a hole along the trace line using a drywall saw for drywall or gypsum board plaster and a reciprocating saw for wood lath plaster.
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.
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.
Use a drywall saw and knife to cut drywall and gypsum board plaster, use a reciprocating or keyhole saw to cut wood lath plaster. With the framing exposed, use a small saw to cut two vertical kerfs in the plate about an inch apart and then use a wood chisel to chip out a notch about ½inch or so deep, between the cuts.