There will probably be several options for an electrical source to serve a new outlet. For instance, it is likely there are several suitable wall receptacles in any given room to extend the circuit to another room or another floor of the house.
Mark a straight line along the wall a few inches from the floor just below the top of the baseboard. Cut the wallboard along this line using a drywall saw for the hollow parts between the studs and a drywall knife to cut over the studs.
When running new wiring pay attention to the amp rating for the circuit you are extending. For a 15 amp circuit use 14 awg (american wire gauge) cable, for 20 amps use 12 awg, 30 amp: 10 awg, 40 amps: 8 awg, 50 to 60 amps: 6 awg. Most lighting and receptacle circuits will be 15 amps and make use of 14/2 or 14/3, but some of these circuits may also be 20 amps, so be sure of the rating and use the proper cable and devices for your project. Depending on the gauge and box depth, there is a limit to the number of wires allowed inside an outlet box. If adding new ones would force exceeding the limit it may be possible to add a junction box to the circuit.
This page offers some options for locating an electrical source for a new wall receptacle or a light fixture, and running the new cable required. To make this job easier, it’s best to have a second person at one end or the other of a new run, to sight the end of the fish tape and help guide cable. Also be sure to always turn off the affected circuits before working on household electricity.
Use a straight edge held flat against the top of the base cap to keep your line straight as you pull the knife through the caulk several times until it’s cut cleanly.
If the wiring is correct turn the power off and install the device in the outlet box. Carefully fold the wires to fit into the box and push the device with your palm until it sits flat and is aligned with the mounting holes. Drive the mounting strap screws and shift the replacement of the device left or right as necessary to square it in the box as you tighten them down. Install the cover plate, turn the circuit back on and test the device again.
Insert a clamp, with wires attached, into the junction box hole and from inside the box, push the included nut over the wires and onto the clamp threads. Turn the nut as far as possible onto the threads and then use a screwdriver and hammer to tap it down until it’s tight.
A heavy duty circuit switch located in the service panel and designed to instantly shut off electricity if an overload or short occurs. Circuit breakers are rated for the amount of current they can carry. 15 amp circuit breakers are used with 14 gauge cable for general purpose lighting and receptacle circuits. 20 amp breakers are used with 12 gauge cable for heavier loads such as microwave ovens and dishwashers. 30 amp breakers are used with 10 gauge wire for an electric water heater or clothes dryer. A large kitchen range will require a 50 amp breaker and 6 gauge wire.