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Wiring a Light Switch

The easiest wiring of a light switch you can do is with a single-pole standard light switch.   View the following wiring diagram instructions on the wiring of a switch and replace that switch today!  This article explains the two most common methods for wiring a basic light switch.


There are two methods for wiring a basic on/off (single-pole standard duty) switch to a light or a set of lights.

One method is to bring the power supply in to the light fixture outlet box, and then use what is called a “switch-leg drop” to the switch box, and the other way is to bring power in to the switch box, and then run the “switched” cable up to the light or lights.  The second method is by far the best way, especially if you are using the switch to control more than one light outlet.

Method #1 (The switch-leg drop)

Step #1

Run your 2-wire power feed cable to the outlet box for the light fixture.  Then run a 2-wire cable to the outlet box for the switch that will be used to control this light.

Step #2

Properly install the cables in the device boxes and terminate your ground wires as per code rules and accepted trade practices.

Step #3

In the light box, splice the black power wire in, to the white wire going to the switch.

*Note that this is one of the few times that it is acceptable to use a white wire as a hot conductor, providing that you identify this as a live wire by using a piece of black tape, or a permanent felt marker to color in a section of the wire close to the connection point so as to clearly identify that the wire is not a neutral conductor as one would normally expect!

The white neutral conductor from the source is connected to the white wire(s) or neutral terminal of the light fixture.  The remaining black wire returning from the switch will be connected to the black wire (s) or the hot or live terminal for the light fixture.

Step #4

In the switch box, the white wire (which is a hot wire as described above) is again identified as such, and is connected to one of the terminals of the single-pole switch (It doesn’t matter which of the 2 terminals, but  personally I always use the bottom terminal for hot, the top terminal for the switched wire).  The black wire is then connected to the other terminal to complete the circuit.

Method #2 (Power to switch, then to light or lights)

Step #1

Run your power feed cable in to the switch outlet box first, then run a cable from the switch box up to your light outlet box.

Step #2

Properly install the cables in the device boxes and terminate your ground wires as per code rules and accepted trade practices.

Step #3

At the switch box, splice the incoming neutral or white wire to the white wire going to the light box.

Connect the black live wire from the power cable in to one of the terminals on the single-pole switch (again, it doesn’t matter if you use the top or the bottom terminal of the switch, but I prefer to use the bottom terminal for the hot wire), and then connect the black wire from the cable going to the light fixture to the other terminal of the switch.

Step #4

At the light fixture, the white wire connects to the fixture neutral (white) wires or neutral terminal, and the black wire connects to the fixture live(black) wires, or hot terminal (terminals are found on basic fixtures such as keyless lampholders).  If you have more than one fixture to be controlled by the switch, then you would now run cable from this light fixture to other lights that you would like controlled by the switch.

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  • WALTER NYUKURI

    It’s wonderful having all these information and would like to be advised on how to become a certified electrician and get my licence.I will be able to pay for whatever fee that is needed to go through the course on line.

    Is it possible for me to learn on line and be awarded a journey man electrician Licence.

    Kind regards,

    Walter.

    • admin

      Walter.
      You would have to check with the educational requirements for you particular location, but usually training for an Electrician is by an Apprenticeship program.

      • Bob

        do you have an apprenticship program?

  • Bob

    I want to finish my basement and have some knowledge of electricity and want to put a switch in line with the 4 light fixtures that are pull strings, how?

  • Kurt

    Who knew that wiring a switch could be so darn complicated? All I wanted to do was replace a defective, worn out 3 way switch!

  • matt cronin

    We were upgrading our storage lighting from two lights, one on switch,one pullstring to two on switch and five on pullstrings. We got the lights installed and wired but had a heckuva time figuring out the connections for the switch. We had a total of five wires in the box: one for run of new lights, one for single new light, one from switch, one from power feed, one out to bathroom. We tried a bunch of combinations but kept tripping the breaker. Then we searched and found your page. EURECKA !!! It was the perfect answer (method 1, step 3) and detailed EXACTLY how to connect the switch wires to the power and light wires. Thanks alot for helping us finish this project !!
    Matt and Trisch

  • Catheryn Vanschaick

    I hope you would not mind if I posted a part of this site on my univeristy blog?

  • A. M. Burton

    I plan to remove a light fixture in the kitchen and replace it with 8 recessed fixtures. I want 6 of them to come on first and the other two to come on with another click. What type switch do I purchase and what would be the wiring diagram for this set-up? Thanks.

  • John

    I installed a new light fixture in the ceiling. When I also replaced the switch on the wall I used a single pole switch. When I turned the power back on the ceiling fixture went on but the switch wouldn’t turn it off. I did wire the white/hot wire to the top screw on the switch. Is the switch not working because I need a 3 way switch? The old switch did turn on 2 ceiling fixtures/chandeliers, but I had them removed years ago. Advice?

  • John

    I installed a ceiling light fixture and when I turned the power back on it was working yet the wall switch wouldn’t turn it off that I had installed. The old wall switch turned on two ceiling light fixtures. Do I need a 3 way switch rather than a single pole switch?

    • Siegfried H. Ward

      No.  3 way switches are for large rooms or hallways where there are two (2) switches that run the SAME light.  In your case, you have wired your light improperly, giving it power without going through you switch first.

  • ramesh

    s correct….

  • Rick

    I have a light switch in the bathroom that has three black wires hooked into a single pole switch. I found that the hallway light just outside of the bathroom is connected through this switch. Can you please advise proper terminals to make both lights active. There appears to be only one live black wire when I tested them.
    Thank you

  • ken cooper

    I have 2 new outside lights and i am trying to wire them up to an exiting outside light switch, which already has 2 brown wires in. I have got a brown and a neutral. can you tell me where they fit please.
    regards
    Ken

  • naol

    tankyou

  • Kenny K.

    I want to thank you so much for the detailed awesome info that you give for wiring a light switch.

  • Bob

    I’m trying to add(2) fluorescent light fixtures from a switch that currently operates (10) light, But the switch has a 3-wire cable to a j-box that has a light fixture attached. I’d like to start at the j-box w/ light, but I’m not sure how to make the connection from there to the 1st fluorescent fixture.

  • sanju

    electrical

  • Scott

    See if I can explain —-
    Have a switch (we think to two lights in a den (can’t figure what else it would be too and makes since – no lights wired or mounted at this time (looks like nothing since house was built in 1977). Wires in den from wall – on left side one marked to line on right, the other not marked, but guessing it is from the switch. The right side has only one set of wires coming from it. Thinking…left light has in from switch and circuits to light on right. Have electrical tester, no juice from any of the wires in the den. Pulled plate and switch out from wall. Looks correctly wired. I get a low light on tester. Not full like if you stuck into an electrical outlet. Does this mean it’s not getting enough juice, I’m wired incorrectly, or is it a connection from somewhere else that is the problem (like panel). Thanks

  • Pmtn78

    looking to wire two switches for two seperate light fixtures can you explain how this is done?

    • Waldo

      Depending where the power is coming from. If power comes into the switches first then the Black wire feed stays in the box and connects to each switch. The white joins together with the wire to each light feed and the black from each light return joins to the corresponding switch remaing screw.
      Situation is different if feed comes into one of the lights first.
      Remember! White feeding the circuit is the neutral and must continue to each light as white.

  • john

    do you need a wire with black, white, red, and ground wires to run a light switch or just black, white, and ground? 

    • The Internet Electrician

      It depends on the circuit you are trying to wire. I’d need more details on what you are trying to accomplish.

    • Bsquires49

      black, white and ground

  • Shirleymarlene

    I  don’t see any answers.  Where is the answers?  I just see questions.  I need the info now.

    • The Internet Electrician

      Send me your question and I’ll get you an answer Shirley. I can’t get to all the comments as quickly as I’d like to, but if you need an answer, drop me an e-mail.

    • Anonymous

      Send me your question Shirley, and I’ll get you an answer.

  • Richallen45

    I have an outdoors light that I would like to control with two switches, let me explain.
    I have a switch box which controls an outlet across the room, I would like to run from the out et a line to the outdoor light, between the outdoor light and the outlet I would like to add another switch to control the outdoor light.
    The original switch would be the master to the outlet and the switch from the outlet and would control the light out doors

    • The Internet Electrician

      That will work. It’s just not the ideal situation, but you don’t have enough wires to make this a proper 3-way switch network.

    • Anonymous

      This will work, just not the most desirable situation. A 3-way network would be best but the existing wiring will not allow for that.

  • Briangilligan83

    Hi,

    I just put in a new light fixture in the bathroom, when I connected everything back together and now the trip switch keeps turning off, I put all the wires back the way they were and I don’t know what I’m doing wrong. The light in the bathroom is now on and also the socket but I had to disconnect the wires from the light switch so the trip would stay on!!! Can anyone help me with what’s happening??

    Thanks

    Brian

    • Bsquires49

      you have taken the light switch out of the circuit

  • Randy

    im installing a ceiling vent into my bathroom and thought i had wires all good now when you turn light switch on the lights go out and vent goes off and when i turn light switch off the vent goes off and lights come on? what im i doing wrong?

  • Captainzenitram

    what size wire should i use from a 400 amp service to a 200 amp subpanel
    in Az

  • Lianne

    I have 3 recepticals on the same wire and I want to add a light switch the the middle receptical. How do I wire the receptical with the 3 wires?

  • Mitchell

    I jumped a light switch from a receptacle and the breaker tripped, what did i do wrong

    • The Internet Electrician

      It depends what you were trying to accomplish with the switch. If it was to make the receptacle switched, my guess is that you connected the hot and the neutral to the switch causing a short circuit condition when you closed the switch. I need more information.

  • Mitchell

    Does anybody answer these questions?

  • Shaaron Sharoba

    i want  uae hig racing building wiring diagrame and electrical room   l v room diagrame

  • Estes_cathy

    If I only have a black and white wire in my light switch receptical can I still install a motion sensitive device without a ground wire?

    • Siegfried H. Ward

      If by “motion sensitive device” you mean “motion sensitive SWITCH” then yes, you can install it in your switch box.  Because it takes the place of your old switch, nothing is really different except that you don’t need to reach over to turn the switch on/off with you hand.

  • Jimpursell

    The white wire on a light gray background is not clear.

  • Jimpursell

    Your language is confusing.  Rather, why not simply say:  ”Connect the white wire from the power source to the white wire going to the load.  Connect the black wire from the power source to one switch terminal and connect the other switch terminal to the black wire going to the load.”  

  • Alive Sc

    Presently I have 2 lights on a switch, and I want to add an outlet so that the outlet is live, even when the switch is off.  I wired the outlet from the first light but it only works when the switch and lights are on.  The second light has a wire from the first light, also.  Should I wire the outlet from the second light?  What is my solution?

    • Bob Pfister

      `you have to run a another wire from the switch to your rec. splice them in to the wires entering the switch be for they are connected to the switch
      `

  • Mtrain2k

    When the power to a light switch originates from the receptacle,the neutral white now becomes the hot wire…..right? So to power another switch (ie dimmer) the neutral is now the hot wire to the dimmer?

  • timmi59

    I have a 3 way switch for my outside house lights (1 in garage 1 in house) I want to make on a timer switch (garage) is this possible?

    • Siegfried H. Ward

      If you can find a timer switch that is a 3 way design, then yes.  Otherwise, you’d have to rewire your outside lights without the 3 way switches.

  • Emerymtd

    Sir, I’ve had a dusk to dawn light mounted to my garage for 15 years.  It recently stopped working so I replaced it with a Walmart special.  The replacement only lasted weeks.  After trying a new bulb, then a new sensor, I noticed a melted glob of plastic in the inner workings of the fixture.  I got another light and the same thing happened.  What’s going on?

  • Julious Humphrey

    I have two sets of wires a black and white set. I am putting in a on and off light switch. The switch has 2 screws on one side and a ground at the end.
    Tell me do I put 2 of the same color on each end or do I mix them up.

  • Johnj22

    I have two lights in the powder room, each controlled by a separate switch which are mounted next to each other.  Is there anything that I can buy to “join” the two switches so they operate as one….I was thinking of a bar or clamp, similar to circuit breakers for 220 electric lines.

  • Larsonjanice

    my light fixture doesnt have white and black cables only one silver cable that splits into two separate cables (and then a little wire that is exposed, has no plastic covering at all – am assuming thats the ground. how do I know which cable I should connect to the white and which I should connect to the black. thank you

  • Aemerson1833

    trying to put a dimmer switch on a ceiling light. The current switch has 2 black wires to the off position one to the on and a ground. The dimmer has only 3 wires, 2 black and a ground. Can I just put the two to one?

  • Jordanbandola

    i have two lamps it is controlled in one location (SPST switch) if the switch is off, lamp one is light on but if i turn on the switch lamp one is  light off while lamp two is light on.. give me a diagram how to install this problem
     

  • Netbaby12

    i removed an on off switch that only has two sets of wires only. one black set and one red set. the new on off switch has 4 areas to screw wires into them but i only have 2 sets a red set and black set. what do i do now?

  • Netbaby12

    i removed the old light switch it only has two terminals. i have 2 sets of wires 1 black and 1 red. the new light switch has 4 terminals. what do i do now?

  • Ronlabonte61

    i have a wire comming from they light in the next room i want to know can i install a switch from that to a light?

  • Wgdriver

    How many lights can I connect to one breaker?

    • rodjaxx

      How many Amps is the breaker?
      For a 15 Amp breaker you can run about 18 100watt light bulbs or 1800 watts total or 120 watts per amp (breaker rating) on 120V
      house wiring

  • Rmurphysr

    i have a two wire black white and ground, from service to a light and then to the switch how do i wire another light in between the switch and light

  • Rmurphysr

    can you run 2 lights in the  switch leg drop?

  • Dippy1348

    I’m replacing an old light switch to a new one.  The old one has 2 black wired and one red wire coming out of the back of the switch.  The new switch had 2 screws on one side and a ground at the end.  What wires go to the screws on the new switch, being there is no white wire?

  • lenclark

    I recently replaced my ceiling light in my dining room.  I replaced the old ceiling fan light and it was wired a little different. It was wired to 2 switches on the wall, one for the fan and one for the light.  The switch for the light also had a dimmer.  When I disconnected the old fan/light, it left me with 5 wires plus a ground wire.  The wires were 1-black, 1-white, 1-green, 1-red, and one insulated black wire.  I used the black and white wires to connect the new light and it worked, Unfortunately it’s on the switch used for the old fan and not on the switch with the dimmer. 

    My question, I want to re-wire the new light to go on the switch with the dimmer.  Do I disconnect what I had and re-connect with the red and green wires?  Also, odd enough, but now my front porch light doesn’t work which I believe has to do with the insulated black wire.  When I disconnected the original light, this insulated black wire had a small white lead wire that connected the insulated black wire to the white wire. 

    Any suggestions?

  • joe

    Iam connecting an on off switch for a light fitting .the switch only has 3 connections 2 neutral and 1 live connections.How do I connect my 2 incoming wires and my 2 out going wires

  • laddyboy

    I took out a ceiling fan and want to replace it with a light fixture. I have two romex into the switch box and two romex into the light box. If I just put black to black and white to white in the light it just stays on all the time. How do I wire this as it appears I have power into the light and into the switch?

  • wayne

    I have 2 red wires, 2 white wires and a ground coming out of a switch box. I want to install a 3 way switch. Other than the ground, where do I attach the red and white wires to the switch?

  • Buggs Peyton

    How can a second light fixture be added to the switch opposed to the first fixture?

  • PhoneGuy

    Hey there. I’m adding an exhaust fan to my bathroom. At my light switch I only have one Romex coming in, so feed at light. I ran a new piece of Romex from new fan to switch area, installed double gang box, have second switch, but can’t seem to get right combination to get both devices working. Suggestions?

  • Mason

    I have s double light switch that works an outlet and an outside light. After replacing the outside light fixture both the light and outlet stopped working. The outside light worked fine for a day then began to flicker and everything went out. I replaced both switches and the outlet. The box for the switches has two grounds, 3 white (neutral), and 3 black (leads). 1 lead splices and goes to the hot on each switch. The other two black wires go to the bottom silver screws. The 3 whites are coupled together with a connector cap. I am getting roughly 120-123 volts on each black but nothing through the neutral when the lights are switched to on. The outlet nor the outside light will work. I have no idea where to go from here.

  • Jim

    I have a 20 amp breaker, when i turn the switch on it trips the breaker. The switch is a 2 pole switch & nothing is connected to it. I have tried 3 different switches & 2 different breakers. Why is this happening?

  • Tom_Hayes

    I have recently installed a bathroom vanity light in a circular hole that was previously covered. there were only two wires in it. one black, one white. After the installation, the lights will not turn off. There is no pull chain or built in switch. There is a dome light in the bathroom that is controlled from a wall switch but I was not able to see if there where anymore wires leading to the circular hole that may act as a switch wire. Is there anything I can do before having to cut into my wall?

  • Steve Jones

    I removed an old, deteriorated light switch and replaced with a new switch, and no matter how I wire it, nothing happens. Two black wires come out of the box and that’s all. When I touch one of the wires to the metal box, the light comes on.

    What the heck?

  • LJones

    Great advice. Clear and very understandable. Thank you!!!

  • jerry

    I have a breaker which is tripped but the circuit is still live. When I try to turn the breaker to the on position I get a very loud pop and the breaker goes to the tripped position.

  • austik

    I have a pool light switch that has white and black wires i got new light switch for new LED light and switch instructions say white to white, red to red, black to black. How should I connect it? Thanks

  • liam

    I’ve changed the switch but when I flick the fuse on one light works normally and the other light stays on permanently and can’t be turned off by the switch how do I fix this problem?

  • Mark

    I’m replacing an old ceiling fixture in a closet. It had a black hot wire and two white wires, each connected to its own connection screw. It also had a place for another connection (basically 4 connection screws with one black and two white connections and one empty).
    My new porcelain fixture has a connection for a hot and a neutral wire, leaving one white wire unconnected. I connected it this way and now am having trouble with my electricity in over nearby parts of the house (microwave, dining room).
    Should I connect both white wires to the same connection on the fixture?

    • Internetelectrician

      Yes Mark, you need to pig-tail splice the two white wires together with the ‘tail’ going to the neutral connection on the new porcelain keyless fixture. The problems you are having is a result of breaking the neutral path in that circuit.

 

The Basics of Household Wiring DVD

"If you're looking for a good reference to help you understand simple home wiring, I personally recommend 'The Basics of Household Wiring' DVD".

Terry Peterman, the Internet Electrician
 
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