Thursday, March 1, 2012

How Do I Wire a 3-Way Switch to Control a Light PLUS Keep a Duplex Receptacle Hot


How Do I Wire a 3-Way Switch to Control a Light PLUS Keep a Duplex Receptacle Hot

This is a question from a site visitor who was wanting to know how to wire a specific 3-way configuration.  The twist comes with the addition of a new duplex receptacle which he wanted to keep ‘hot’ all of the time, while still controlling a light with the 3-way switch.  This article describes the possibilities of this scenario and the steps to take.
Q: How do you wire a new duplex receptacle from a 3-way switch so that the new receptacle is always hot and the 3-way switch continues to only control the light fixture?
A: You may not be able to accomplish this, depending on how this 3-way circuit is wired.
The only way this will work properly is if the power source for this 3-way network enters this box first.
If not, you might have switched ‘hot’ conductors only, or if you do have a neutral, any of the hot conductors that you attempt to splice in to will not be hot all the time (it will depend on the switch positions).
You need to determine how the circuit is wired. If the power source does enter this box, then you could add a receptacle providing the box is large enough (deep box) to accommodate these additional wires because a normal sized metal switch box can only have 5 wires in it, and you will add two making a total of seven.
Here is a diagram of how this receptacle could be added in the proper circumstance.

How To Wire a Switch/Receptacle Combo Device


How To Wire a Switch/Receptacle Combo Device

Lately I have had many site visitors asking me to write an article on how to wire a duplex switch and receptacle combination device.  While the switch/receptacle combo device is not common in the home, they have several unique applications where they can be very useful!
As with any electrical project, make sure that you take all necessary precautions, most important being to make sure you shut off the power.  Always review the safety page on our website.
Another valuable resource available on our site is “The Basics of Household Wiring DVD”, which is also available as an instantly downloaded e-book.  Follow this link to get your copy.
The switch/receptacle combo device is set up like a duplex receptacle, but has a 15A single-pole switch in one half, and a single 15A, 125V receptacle in the other half.  They can work in conjunction with one another, or they can be connected and used independent of each other.
Here is a diagram showing the internal function of the switch/receptacle combination device.
Here is an actual picture of a Leviton Switch/Receptacle Combination Device.

I will discuss three different possible scenarios where a switch/receptacle combo device such as this would come in handy.
Scenario #1
In your garage or shop, you would like to install a task light, like a florescent light fixture over workbench.  However, the walls are all finished so getting a new wire to a switch and then up to the light is not that simple.  However, you have a receptacle just above the bench that you can get your power source from.
You can change this duplex receptacle to a switch/receptacle combination so that you still have power in the outlet, but can use the switch to control your new overhead task light.  Fishing in a wire from the receptacle to the light fixture is fairly easy, so this is how you would wire the switch/receptacle combo device in this situation.
Scenario #2
A typical example of this situation is if you had the same scenario as above, but with a 3-wire circuit, such as in a kitchen split receptacle, and wanting to add some under-counter lighting for example.
Just as the receptacle that you replaced will have the tab on the hot side removed, here we have to remove the tab on the device as well.  This will put the light on a different circuit as the receptacle, but again will give you the desired result of a usable receptacle, and a switched light fixture without a difficult wiring renovation.
Keep in mind that this isn’t the best situation, as you now lose the required amount of circuits in the kitchen. However it is an example of how we can have the switch and receptacle operating independently from one another on different circuits.
Scenario #3
Here is a situation where your desired result is a receptacle controlled by the switch in the combination device.
Let’s say you have a task light for your shop, and it is cord connected and designed to be mounted over your work area and then just plugged in to an outlet.  Instead of plugging the light in and out every time you want to control the light, this will allow you to keep it plugged in and use the switch for control.
So there you have three examples of where a switch/receptacle combination device like this can come in handy.

Outdoor Lamp Post Installation Questions


Outdoor Lamp Post Installation Questions

Installing an outdoor lamp post along a driveway is a terrific way to illuminate the exterior of your yard.  In addition to lighting a path to your home, this type of lighting can enhance the safety of your yard by letting you easily see any potential hazards, as well as deter any unwanted criminal activity.  The installation of an outdoor lamp post is one of those DIY projects that can be safely taken on by a competent DIYer.  I recently received an e-mail from one of my website visitors who had a question regarding the installation of an outdoor lamp post; more specifically, whether it would be necessary to install an electricalbox along with the lamp post.  The following video and article answers this question.


Q:  I’m going to be installing an outdoor lamp post alongside of a driveway. I have a new lamp post assembly, which came with an 18/2 SJ cord prewired from its’ 3-lantern head down to the base of the pole assembly. The pole assembly will be mounted onto a 2ft deep concrete footing with a PVC conduit installed inside of the footing. A 14/2 NMWU cable will be run underground from the house to the lamp post.
Since the lamp post has an 18/2 SJ cord prewired down to the base of the pole assembly, I am wondering if the underground cable connection should be made at the base of the pole, where the prewired 18/2 SJ cord terminates –OR- should I remove the prewired cord, and run the underground cable through the pole to the lantern head? If the connection is to be made at the base of the pole, will it be necessary to install an electrical box on top of the footing where the base of the pole will sit? The base of the pole has also a large canopy. – Stephen

A:  Stephen, the base of the lamp pole itself is an approved junction box for the termination of the underground cable and connection to the SJ cord that is prewired from the lantern heads on down to the base.  When fixtures get appropriate approvals from accredited agencies, they approve the entire fixture as a whole, and a suitable location for the electrical connections is a part of that inspection.
You could run the NMWU cable up to the lantern head, but only if that is more convenient for you in some way, like easier access to the splice should something go wrong.  The advantage of that would be one less set of splices, thus one less potential trouble spot.
The only issue you may have in your project is the size of the underground wire.  I would check with your local electrical authority to make sure that #14/2 is large enough.  Some jurisdictions specify that 12 gauge wire is the minimum size allowed for underground installations.
So in conclusion here; no, you do not need to install a junction box on top of the PVC conduit at the base of the footing, the fixture itself is approved for the electrical connections.  Enjoy the light and good luck with the outdoor lamp post installation project!

Tuesday, February 28, 2012

5 Reasons to Have a Bathroom Heater Fan

If you need to replace the exhaust fan in your bathroom, consider replacing it with a bathroom heater fan instead. Bathroom heater fans provide all the functionality of a standard bathroom exhaust fans as well as providing heat to your bathroom. Here are 5 reasons why you should have a bathroom heater fan in your bathroom.

1. Removes Moisture and Odors from the Air

Like standard bathroom exhaust fans. Bathroom heater fans also remove moisture from the air in your bathroom. Allowing too much moisture to build up in your bathroom will fog your mirrors, promote the growth of mold and mildew, make your floors and fixtures slippery and usually provide for a overall more uncomfortable experience in your bathroom. The fan portion of your heater fan will draw moisture out of the air and pass it outside of your home’s duct tube system. In addition, the fan will also help remove unpleasant odors from your bathroom when it is necessary.

2. Keeps You Nice and Warm

The primary purpose of a heater in the home is to help keep you warm when temperatures are low. Most bathroom heater fans use some sort of infrared heat lamp that heats quickly and is ideal for heating small spaces such as bathrooms. Bathroom heater fans heat quickly but do not provide so much heat as to be uncomfortable or cause skin irritation. Allowing your bathroom to heat up a minute or two will make getting undressed for your morning shower a more comfortable experience. Your transition from the shower to the towel bar will be easier as well.

3. Helps Keep Fixtures and Mirrors Dry

Adding a heater to the exhaust fan in your bathroom will also help you keep your fixtures drier and free from mold and mildew. While standard bathroom exhaust fans do help some in this regard, bathroom heater fans do a much better job of keeping your mirrors from fogging up and keeping your sink and toilet dry to the touch. Drier mirrors and fixtures will mean less mold and mildew buildup and helps make cleaning your bathroom quicker and easier.

4. Inexpensive to Buy and Run

If you need to replace the existing exhaust fan in your bathroom, purchasing a quality bathroom heater fan will not add much more expense. In fact, the price difference between bathroom heater fans and standard bathroom exhaust fans is probably much less than you think. If you wait for bathroom heater fans to go on sale at your local home improvement store, you can save even more money.

5. Easy to Install

Most bathroom heater fans are very easy to install, and even come with complete instructions that show you exactly how to do it. Installing a bathroom heater fan is an excellent DIY project for even the novice home handyman and can generally be completed in an hour or two. To install a bathroom heater fan, you simply need a few basic tools and a step ladder.

How to Install a Light Fixture


what you'll need

  • Lighting Fixtures
  • Outlet Boxes
  • #14-2 Wiring
  • Saber Saw
  • Knife or Stripping Tool
  • Fluorescent Tubes
  • Hand Drill
  • Folding Rule
  • Stud Finder
  • Parts for Fixture Connections
  • Hanger Bars
  • Keyhole Saw
  • Pliers
  • Fluorescent Starters
  • Screws
  • Marking Pencil
  • Screwdriver
These tips and suggestions on how to install wall and ceiling fixtures can help you complete a better installation in less time and with less effort.

PARTS NEEDED FOR TYPICAL FIXTURE MOUNTING
Most wall and ceiling fixtures–other than recessed fixtures–fit into standard electrical outlet boxes and are usually easy to mount.
These are the typical parts required for installing wall or ceiling fixtures.
Most fixtures are mounted by a fixture stud or a fixture strap. Occasionally you need an extension nipple or a plain nipple for mounting certain fixtures.
Any additional mounting devices required for special types of fixtures are usually included in the materials furnished by the manufacturer. Read and follow the manufacturer's instructions carefully for a neat installation.

INSTALLING A CEILING OUTLET BOX
    Occasionally you may need to install a ceiling outlet box before you can mount a new ceiling fixture. Such an installation requires some time and effort, but is not too difficult.
    The first step is to mark the position on the ceiling where the new outlet box is to be located. Determine the exact dimensions of the box and cut a hole in the ceiling where it will be located. Use extreme care and cut the hole to the exact size and dimensions.
    There are a number of different types of boxes and mounting devices available. The boxes with the expanding devices on the sides are generally recommended for use with lightweight lighting fixtures only. This is because of the relatively small area to which they anchor. Madison hangers also fall into this category.
    There are boxes designed to be nailed to ceiling joists. Angled nailing holes are provided. They make it possible to position and nail the box into a hole cut into the ceiling. The hole for this type of box needs to be cut next to a ceiling joist.
    Most of the better mounting bars have an expanding feature that allows them to tighten between the joints. These bars must be inserted through a hole cut in the ceiling. Depending on the type of mounting bracket, some will lay almost flat against the surrounding drywall above the ceiling. Others will require enough clearance to attach an electrical box to the bar. You will usually want the bottom of the box to be flush with the ceiling surface.
    Cut a hole in ceiling to the exact dimensions, and mount the ceiling outlet box with a hanger bar.

    Next, insert a hanger bar through the hole to rest firmly on the back of the supporting ceiling. Position the hanger bar carefully so it is firmly supported.
    Connect the feed cable to the ceiling outlet box, as illustrated. If the feed cable is connected to a power source, turn off all power at the main switch before connecting it. Secure the electrical wire to the ceiling outlet box with a cable clamp.
    Now, mount the ceiling outlet box with the wire attached on the hanger bar with the attached nipple and locknut. Be sure the current is off at the main switch. Connect the feed cable to a power source at an outlet box. Now you are ready to hang the ceiling fixture.


    INSTALLING WALL FIXTURES
      You can install wall fixtures in regular outlet boxes with a strap and nipple.
      Click on drawing above to view animation.
      As a rule, you can install wall fixtures in regular outlet boxes with an ordinary strap and nipple.
      Of course, different types of wall fixtures have different connecting arrangements, but you can usually attach the strap right to the fixture outlet box with screws. Then you can attach the wall fixture to the strap with a nipple and knurled cap.

       
      If a box has a central stud, you'll only need an adapter and nipple.
      If the box has a central stud, you will need only an adapter and a nipple to attach the fixture. An adapter is screwed onto the stud, the nipple is attached to the adapter and the fixture is attached to the nipple.
      Wall fixtures are usually quite simple to install. Manufacturers of wall fixtures design different mounting arrangements. The manufacturer will usually include complete installation instructions with the fixture.
      Read and follow the manufacturer's instructions carefully. Always turn off the current before installing any fixture.

      INSTALLING CEILING FIXTURES
        The ceiling fixture is attached with a strap if the box has no stud.
        Some ceiling outlet boxes have no stud in the center. In such cases, the ceiling fixture is usually installed with a strap that is screwed directly to the threads in the ceiling outlet box. The ceiling fixture is then attached to the strap with screws.
        The mounting arrangement illustrated will support most lightweight ceiling fixtures. Such an installation is simple, fast and meets most wiring codes. Solder-less connectors speed up the job.


         
        With a center fixture stud, attach the strap with a locknut.
        If the ceiling outlet box has a center fixture stud, mount the fixture by attaching the strap to the center stud with a locknut.
        Once the fixture strap is firmly attached to the fixture stud with the locknut, screw the fixture canopy to the strap with two screws.
        If solder-less connections are code–approved in your area, use them to connect the wires. If not, use whatever is specified by your local code. Any wires that are joined should be completely insulated. Also, use extreme care when connecting the wires. Black wires generally are attached to black wires, white to white and green or copper to green or copper. Follow any supplied wiring diagrams carefully.
        Drop fixtures are often mounted with a hickey that screws to the center fixture stud.
        Heavier drop fixtures are often mounted with a hickey. This hickey screws to the center fixture stud.
        Attach a nipple to the lower section of the hickey with a locknut. Then mount the fixture canopy to the nipple with a collar.
        Hickey use in mounting drop fixtures varies according to the design and weight of the ceiling fixture. Almost all heavier drop fixtures require a hickey.
        Remember: Be sure the current is shut off at the main switch before attempting any mounting.

        INSTALLING CHANDELIERS
          You can mount chandeliers right into ceiling boxes as replacements for ordinary ceiling or drop fixtures. However, the mounting style varies according to the style, weight and design of the chandelier.
          When installing heavy chandeliers, it is a good idea to check the existing box. It must be mounted firmly enough to carry the weight of the new fixture.
          Mounts for chandeliers vary by style and design. This shows a common method.

          Figures illustrate a common mounting method for lighter-weight chandeliers. If the manufacturer recommends a different mounting, complete instructions will be provided. Read these instructions carefully and follow them in detail.
          The mounting bracket is attached to the ceiling box with screws. The main rod of the chandelier is then screwed into the strap to provide adequate support.





          Loosen and lower canopy.
          When replacing an ordinary light fixture with a chandelier, the first step is to turn off the current and loosen and lower the canopy of the old fixture. The figure assumes that you are replacing a drop ceiling fixture mounted with a hickey.


          Remove the old fixture to completely expose the wiring.
          Regardless of how it is mounted, the fixture should be totally removed, leaving the wires for the new fixture completely exposed and ready for mounting.


           
          You may be able to attach the new fixture to the original hickey.
          In many cases, you can mount the chandelier right into the hickey used for the old fixture. If a different type of hickey mounting is required, the manufacturer should provide it.


          Some chandeliers bolt to brackets that are mounted on the strap.
          Some chandeliers are designed to bolt to brackets that are mounted right onto the mounting strap. In this case, the mounting bracket is attached to the nipple which is placed in a firm position with the locknut.
          Then, mount the fixture to the brackets that are affixed firmly to the mounting strap. Use nice, decorative nuts to give a neat appearance to the canopy of the chandelier.
          In other cases, the strap bolts to the box and the fixture bolts to the strap.
          Other chandeliers must be mounted to the outlet box by a regular fixture strap. The strap is mounted to the threaded section of the outlet box, and the canopy is then mounted directly to the mounting strap.

          MOUNTING FLUORESCENT FIXTURES
            Studs, nipples and straps are used for mounting fluorescent fixtures.
            Fluorescent fixtures are usually mounted to an ordinary outlet box by studs, nipples or straps. A fluorescent ceiling fixture may be easier to mount than an ordinary drop or ceiling fixture.
            Two types of fluorescent fixtures are available. Mounting either type is basically the same, but the wiring arrangement is totally different. Follow the manufacturer's instructions carefully for mounting fluorescent fixtures.


             
            This is the typical wiring arrangement for a starter-type fixture.
            This figure shows the wiring arrangement for a starter-type fluorescent fixture. Of course, manufacturers offer fluorescent fixtures that vary slightly from this design, but the wiring arrangement is basically the same as the kind illustrated.


             
            No starter is required for rapid-start fluorescent fixtures.
            This figure illustrates how to wire rapid-start fluorescent fixtures. No starter is required, but the wiring arrangement and the ballast location are considerably different.
            Some manufacturers may provide slightly different wiring arrangements. If so, study the manufacturer's diagrams carefully and follow them in detail.
            Be sure the current is off before attempting to install the fixture.
            INSTALLING RECESSED CEILING FIXTURES
              You should mount all recessed ceiling fixtures to joists. Your first step in mounting a ceiling fixture, then, is to locate the joists.
              Joists in ceilings are usually located exactly 16" apart. Use a magnetic or electronic stud finder to locate these joists. If you are using a nail-on box, the joist location is very important. Even with the bar, if the hole is too close to the joist, it will make installation difficult, if not impossible.
              You can locate the joists with a small hole and a piece of wire.
              If you do not have a stud finder, you can tap on the ceiling. As you get closer to the joists the sound becomes more deadened. Another way is to drill a small hole and use a piece of wire to help locate the joist.

               
              Cut an opening to the correct size and mount the fixture.
              Once you've located the joist, saw out a hole in the ceiling to the correct size and in a location which permits the recessed fixture to be mounted where it can be screwed or bolted to the ceiling joist.
              Turn off the current at the main switch. Attach the electrical wiring to the ceiling fixture, then mount the fixture in the proper location.


              --
              Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the National Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.  


              How to Install a Light Switch


              what you'll need

              • Screwdriver
              • Three-Wire Feed Cable
              • Wire-nuts or Screw-on Connectors
              • Knife for Stripping Wire
              • Toggle Switches
              • Pigtails
              • Insulating Tape
              • Hand Cleaner
              • Two-Wire Feed Cable
              • Side-Cutting Pliers
              • Outlet Boxes
              • Cable Connectors
              • Keyhole Saw
              • Three-Way Switches
              • Cable Straps
              Follow these tips and instructions on how to replace or install electric switches to save you time and effort. Before beginning any electrical repairs, turn off the power at your service panel, fuse box or breaker box. If you know which fuse or breaker controls the circuit you will be working on, remove that fuse or trip that breaker. If there is any doubt, you can remove the main fuse or trip the main breaker.
              Caution: Tripping the main breaker or removing the main fuse will usually shut off all power to the house. Take the time to read the directions thoroughly to help ensure a satisfactory job.

              THREE BASIC TYPES OF WALL SWITCHES
                The toggle switch floats between contact points in the off position (A), and contacts both terminals in the on position (B).Toggle Switch
                The popular toggle switch has an arrow-shaped armature that floats between the contact points when the switch is in the off position. This armature comes in contact with both terminals when the switch is flipped to the on position (B), thus providing a continuous flow of electrical current to the light or appliance.



                Electrical power is supplied when the contact point is immersed in mercury.Mercury Switch
                The mercury switch has a small hollow cylinder, partially filled with mercury. In the off position, the small contact point is above the mercury level (A). When flipped to the on position, the contact point is immersed in mercury (B). This establishes contact between the two terminals and provides power to the light or appliance.

                The silent switch has a steel spring armature that connects and disconnects the power.Silent Switch
                The silent switch has a steel spring armature that is pressed away from the bottom terminal when the switch is turned off. Flipping the switch lever to the on position moves the steel spring back against the contact point (B), thus establishing contact in the circuit.
                • For installation purposes, all three types of switches can be used interchangeably.

                INSTALLING THE SINGLE-POLE TOGGLE SWITCH
                  Click on drawing above to view animation.
                  The simplest switch system – the single-pole toggle switch – is illustrated. The ordinary single-pole toggle switch provides a means for breaking or feeding electrical current to a light, appliance, etc.
                  The single-pole toggle switch has two brass terminal screws. One wire (usually the black) is cut, then is connected to the two brass terminals. The other wire (white) is uninterrupted from the power source to the light or fixture. 




                  Always turn the wire loop in the direction of the screw threads.
                  When connecting a wire to the terminal screw of a switch, always turn the loop on the end of the wire in the same direction as the screw threads, as shown in illustration (A). If the loop is turned in the opposite direction (B), tightening the screw will loosen the loop.


                  If the wire connects to the terminal screw and then runs on, cut and strip the wire on both sides of the cut. Using a 6" piece of wire with both ends stripped (sometimes called a pigtail) and a wire-nut, fasten the three wires together. Connect the pigtail to the terminal, as in the figure.

                  Wire-nuts or screw-on connectors save time and effort.
                  Use wire-nuts or screw-on connectors to save time and effort when you must make a splice in any electrical wire. Always cover any soldered connection with insulating tape. If soldered sections are rough, apply an extra layer of tape. Insulate the wire an additional inch or two beyond the soldered connection in each direction.
                  White wires should generally be attached to light colored terminal screws such as silver. Black wires should generally be attached to dark colored screws such as brass colored. If the terminal screws are the same color, either wire can generally be attached to either terminal. Green terminal screws are for grounding wires.

                  INSTALLING SWITCH OUTSIDE MAIN WIRING RUN
                    Connect a two-wire cable to the black wires in the last fixture on the wiring run.
                    Click on drawing above to view animation.
                    Use an ordinary toggle switch for installations outside the main wiring run. Shut off all current at the main service panel. At the light fixture, connect the black wire from the switch to the black wire from the light fixture. Connect the white wire from the switch to the black wire from the power source.

                    CAUTION: Anytime it is necessary to connect a white and black wire together, take the time to paint the white wire black at both ends to indicate that the white wire is attached to a power source. Connect the white wire from the light fixture to the white wire from the power source.
                    At the light switch, connect the black wire to one terminal and the white wire to the other. Remember, a green screw is always for the ground wire.

                    INSTALLING IN-LINE SWITCH FOR CONTROL OF ONE LIGHT
                      This illustrates the arrangement for an in-line switch that controls only one light on a two-light line.
                      Shut off all current at the main service panel. A third wire (red) must be added to the power cable for this switch arrangement. The red wire serves as a black wire from the switch to the light or outlet which is to be controlled.
                      Study the diagram carefully. You will note that the white wire feeds continuously from the power source to all fixtures. The black wire is pigtailed on one terminal of the switch, while the red wire attaches to the other terminal. The black wire then runs continuously through to the light or outlet which is not controlled, while the red wire runs from the switch terminal to connect with the black wire on the controlled light or outlet.
                      This arrangement allows the switch to control the first light or outlet while power continues uninterrupted to the second fixture.

                      INSTALLING SWITCH AND CONVENIENCE OUTLET IN SAME BOX
                        Use this as a guide for installing a switch and convenience outlet in the same box.
                        Shut off all current at the main service panel. At the double-switch box, connect a pigtail to the brass terminal on the outlet and another pigtail to either of the terminals on the switch. Wire-nut these two pigtails and the black wire from the light fixture together. Connect the white wire from the light fixture to the silver terminal on the outlet. Connect the red wire from the light fixture to the other terminal on the switch.
                        At the light fixture, wire-nut the white wires from the power source, the light fixture and the switch together. Wire-nut the black wires from the power source and the switch together. Wire-nut the red wire from the switch and the black wire from the light fixture together.

                        INSTALLING TWO PARALLEL SWITCHES FOR CONTROL OF TWO SEPARATE LIGHTS
                          This illustration shows the arrangement for two switches in one switch box for control of two lights.
                          Shut off all current at the main service panel. At the switch box, attach a pigtail to one of the terminals on switch 1. Connect a second pigtail to one of the terminals on switch 2. Wire-nut these two pigtails and the black wire from the light fixture together. Connect the red wire from the light fixture to the other terminal on switch 1. Connect the white wire from the light fixture to the other terminal on switch 2. Be sure to paint the white wire black.
                          At light fixture 1, wire-nut the black wire from the power source and the black wire leading to light fixture 2 together. Wire-nut the white wires from the power source, light fixture 1 and light fixture 2 together. Wire-nut the black wire from light fixture 1 and the red wire to light fixture 2 together.
                          At light fixture 2, wire-nut the black wires from light fixture 1 and the switches together. Wire-nut the white wires from light fixture 1 and light fixture 2 together. Wire-nut the red wires from switch 1 and light fixture 1 together. Wire-nut the white wire from switch 2 and the black wire from light fixture 2 together. Be sure to paint the white wire black.

                          HOW A THREE-WAY SWITCH WORKS
                            This simple illustration demonstrates how a three-way switch operates.
                            The illustration uses open-knife switches to demonstrate how a three-way switch works. Wire No. 1 feeds directly from the power source to the light fixture. However, power must be fed through two wires for the light to function. The flow of power through wire No. 2 is continued or broken by the two switches, as illustrated.
                            Power through wire No. 2 reaches the first switch at the center or common terminal (A). If the knife-switch handle were in position (B), the current would flow through to terminal (D). However, this arrangement would not provide a continuous power flow since the knife switch, as illustrated, is at position (G). The light bulb would not be illuminated.
                            Since the first switch is at position (C), the current flows directly through terminal (E) to terminal (F), then through handle (G) to turn on the light. Note that when either handle is placed in the opposite position, the circuit is broken and the light is not illuminated.
                            Note also that if you swing either handle to the opposite position, the current flow is made continuous and the light goes on again. Obviously, knife switches are not used in an electrical installation. They are used here simply to illustrate what happens inside an ordinary three-way switch when it is installed.

                            THREE-WAY SWITCHES FOR LIGHT
                            CONTROL BEYOND SWITCHES
                              Three-way switches control the lights beyond the switches.
                              Shut off all current at the main service panel. At the light fixture, wire-nut the white wires from the power source and the light fixture together. Wire-nut the black wires from the power source and the switches together. Wire-nut the black wire from the light fixture and the white wire from the switches together. Paint the end of the white wire black.
                              At switch 1, locate the terminal on the three-way switch that is marked as common and attach the red wire. Attach the black wire to either of the two remaining terminals. Attach the white wire to the last terminal.
                              At switch 2, locate the terminal on the three-way switch that is marked as common and attach the red wire. Attach the white wire from switch 1 to either of the two remaining terminals. Paint the end of the wire black. Attach the black wire from the light fixture to the last terminal. Wire the black wire from switch 1 and the white wire from the light fixture together. Paint the end of the white wire black.

                              THREE-WAY SWITCHES FOR LIGHT
                              CONTROL BETWEEN SWITCHES
                                Three-way switches control the lights between switches.
                                Click on drawing above to view animation.
                                Shut off all current at the main service panel. At switch 1, find the terminal marked as common and attach the red wire. Attach the white wire to either of the two remaining terminals. Attach the black wire to the last terminal.
                                At switch 2, find the terminal marked as common and attach the red wire. Attach the white wire to either of the two remaining terminals. Attach the black wire to the last terminal.
                                At the light fixture, wire-nut the two red wires from the switches together. Wire-nut the two white wires from the switches together. Wire-nut the black wires from the power source and switch 1 together. Wire-nut the white wires from the power source and the light fixture together. Wire-nut the black wires from the light fixture and switch 2 together.



                                --
                                Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the National Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.