Some older homes may have rooms with no switch for the ceiling light. The light is turned on and off by a pull chain that is attached to a bulb socket adapter. Since the chain is only a few inches long, most homeowners tie a string to the chain, which continually breaks.
Installing a light switch is relatively simple if you are not intimidated by electrical work. You just need a few supplies from your local home improvement store.
What you will need
You will need a few tools used for electrical work as well as some supplies. Tools include a wire stripper/cutter to cut wire and strip insulation from wire ends, a wire fish tape to pull wire through walls, and screwdrivers for attaching wires to the light switch and the cover plate onto the switch.
Supplies include a light switch and cover, electrical tape and wire nuts to connect ans secure wires, a keyhole saw to cut the hole for your switch, and electric wire.
You will need to use the same gauge (thickness) of wire to install the switch as that used by the circuit that will power the switch. Locate the circuit breaker that controls power to the ceiling light. If it is not clearly marked on the circuit box panel, turn off each switch individually until the light stays off.
The breaker will either be marked fifteen or twenty amp. A fifteen amp circuit will require fourteen gauge wire, while a twenty amp circuit will need twelve gauge wire. Measure the distance from the light to the proposed location of the switch, then measure from switch to ceiling. Add these measurements and then double them, because wiring a switch requires two wires of equal length.
Buy more wire than your final total measurement, because wire often cannot be run in straight lines in walls and ceilings.
Installing the switch
Choose the location for your switch (keep it a few inches from doorways to avoid wall studs) and mark a hole in the wall for your switch. Use your keyhole saw to cut the hole. With the circuit breaker off, remove the ceiling light fixture with a screwdriver. Unhook the wires from the light by loosening the screws that hold them.
Feed the wire fishing cable into the hole for the switch, and feed it steadily upwards in the direction of the ceiling light. You may meet obstructions that will force you to change direction or maneuver the cable until it reaches its destination. This is often the most difficult part of the job.
Cut two lengths of wire according to your measurements, then strip one inch of insulation off both ends of each wire. Hook one end of each wire to the cable and pull them from the ceiling light opening to the light switch hole. Each wire is a bundle of three smaller wires of green, black, and white color. Connect one wire bundle to the left side of the switch and the other to the right side, black wire to brass terminal, white wire to silver terminal, and green to copper terminal.
Connect the wire bundle that is attached to the left side of your light switch to the power wire that was removed from your ceiling light. Twist the same colored wire together, screw on a wire nut, then wrap in electrical tape. The wire bundle attached to the right side of your switch will be attached to the light fixture by twisting same colored wire together, screwing on wire nuts, and wrapping them in electrical tape.
Before proceeding, turn on the breaker and flip the light switch. If it works, turn the breaker off, and screw the light fixture back into the ceiling. Screw the light fixture into the wall evenly with the attached screws, then screw on the cover plate, turn on the breaker, and say goodbye to your old pull chain switch.
If you have any doubts or fears about working with electricity, or if your walls are too frustratingly obstructed, an electrical contracting company like Williams Electric Supply can perform the work easily and effectively.