Wiring A Light Switch

Thomas Alva Edison patented the electric light bulb in 1879. To say that this innovation had a profoundly positive affect on society would be a gross understatement. Although electric lighting is standard equipment for most Americans, there are still parts of the world where it is considered a luxury.

On a recent trip to Southern India we discovered that while most homes in this Asian subcontinent have electricity, often the sum total of a residential electrical service could consist simply of one outlet and one light fixture. Ceiling-mounted paddle fans used to move the sultry Indian air are as prominent in dwellings in that part of the world as doorbells are in America. We returned home with a renewed sense of appreciation for the standard of living that we enjoy in this country.

One interesting observation that we made regarding light fixtures and fans is that they are, for the most part, controlled by a pull string instead of a wall switch. This would only figure since a wall switch requires more electrical work and is, therefore, considered a luxury and not a necessity. Interestingly, one doesn’t need to travel to a third world country to find light fixtures and fans controlled by a pull string. Although this configuration is now the exception, there was a time in this country where such was not the case. Thus, as we seek to improve comfort and convenience, adding a switch to a pull string fixture has become an increasingly popular project.

Is this a project that you should attempt? If you have successfully performed electrical work in your home previously and feel confident working with electricity, then this is a project you might want to tackle. On the other hand, if you are all thumbs and have difficulty using a plumber’s helper, then we suggest that you enlist the services of a qualified electrician. In either case, check with your local building department to determine if an electrical permit and inspection are required.

One of the interesting things about a light fixture is that the power or “hot lead” can originate at the fixture or the switch. We learned this the hard way years and years ago when, as youngsters, we attempted to change a light fixture without turning off the power at the breaker box. In our naiveté we thought that because the switch was off, there was no power at the light fixture. Boy were we WRONG! You can be sure that we didn’t make that same mistake twice.  Thus, before attempting this project, be certain to turn off the breaker or remove the fuse that controls the fixture.

With the power safely off, use a screwdriver to remove the screws that fasten the fixture to the mounting box and disconnect the black wire (hot wire) and the white (neutral) wire from the fixture. The most difficult part of this project is running new wire from the existing fixture location to the new switch location. This may necessitate working in the attic or crawl space, drilling holes and removing small sections of wallboard or plaster at the ceiling and/or walls.

When it comes to wire, use 12-gauge NM (nonmetallic-sheathed) two-wire cable with a ground. NM cable is standard house cable used in dry locations. Two-wire cable contains two conductors (hot and neutral) plus grounding wire, all wrapped in paper and sheathed in plastic. Attach the wire to the framing using the approved staples or straps. The cable should be anchored 12 inches from each box and at least every four feet along the run.

The new switch should be located approximately 48 above the floor. Use a “cut in” switch box which can be retrofit into a corresponding opening in the wallboard or plaster. The new wire between the switch box and the fixture will be used to create a “switch loop.” Thus, the circuit will be closed at the new switch location rather than at the existing switch located within the fixture.

To accomplish this, connect the black wire to the black wire at the fixture. Connect the other end of the black wire to one of the two terminals on a single-pole switch. Next, wrap the ends of the white wire with black electrical tape for easy identification. Connect one end of this wire to the remaining terminal on the switch and connect the other end to the black (hot) wire that enters the mounting box. Connect the bare copper ground wire to metal boxes or tie them to one another when using non-metallic boxes. Use properly sized wire nuts to make the wire connections.

Fasten the new switch to the switch box and complete the switch installation with a trim plate. If the existing pull-string fixture is to be reinstalled, reinstall the mounting screws previously removed and be certain to leave the pull-string in the “on” position. Since a pull-string fixture is no longer needed, this would be an opportune time to install the new decorative fixture that you have been dreaming of. If you really want to go “high-tech” and get fancy, install a dimmer in lieu of the standard single-pole toggle switch.

Once all connections have been made and the switch and fixture are securely in place, turn on the power and test your handiwork. Chances are good that you’ll end up with a grin. Thomas Edison would be proud.

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