How to Wire a Light Switch: The Switch Leg Loop/Drop

hello again everybody I'm Teri Peterman the internet electrician and welcome to another one of my video shorts on current topics at electrical - online.com and of course right here on youtube in this video we're gonna discuss the switch leg drop or the switch loop switch leg however you want to call it it's when the power comes into the light outlet box and then you drop a wire down to the switch location so that you control that light with the switch now prior to 2011 you were allowed to use a two wire cable for this so there's many situations out there where this is the case you only have a black and a white coming down from the light fixture to the switch but after 2011 the code now requires you to have a three wire so that there's a neutral in the box now there's a couple reasons for that one of them being that you no longer have to use a white wire as a hot wire and identified as such but the main thing is that you have a neutral in that box to use for various light controls such as dimmers timers they need a neutral some of these electronic devices and if you don't have a neutral there then you can't install that device properly also it allows you to carry on that circuit from that switch location down to say another receptacle because you do have a neutral so I'm gonna use my demonstration wall in here behind me it shows one of the switch leg drops using a 2 wire I'm gonna show you how that worked and how we identified the conductors but then I'm gonna switch that out to a 3 wire cable so we can do it the way it should be done now so without any further talking here let's get started and as with any electrical project if you're gonna be opening up device boxes first things first shut off that breaker so this circuit is wired with a two wire power cable in a two wire power cable out two devices on the rest of the circuit and then the switch loop down to the switch so how we connect the box here is all your ground wires of course spliced together with a couple pigtails one of them for a future light fixture that requires a ground and another one that goes to the in the back of the box on the ground terminal screw here then the neutrals from the incoming hot so the hot supply table the neutral conductor from the incoming supply and going out to the rest of the circuit they get spliced together they're right here along with a pigtail that comes out to our light fixture in this case we have a plastic chandelier then your hot wires your hot incoming black wire gets spliced to the outgoing hot wire along with the white wire that goes down to the switch and the switch leg drop here's where you're allowed to use a white conductor as a hot conductor as long as you identify it with some black tape or a felt pen just to color that in and let people know that that's meant to be tied into the hot wires so on that white conductor that's now used as a hot that goes down to the switch we'll show you that in a minute comes back on the black wire of that cable and the other side of the switch gets tied on to your light fixture let's go look at the switch alright so moving on to the switch location you remember that white wire in the light outlet box that we identified as hot can be done in a couple different ways coloring it in with some black felt pen or with some black electrical tape wrapped around it to identify it as hot so power comes in on this switch to one terminal back out on this black wire to the light to control the light also in any device box you need to deal with your ground wires here it's a plastic box there is no ground terminal on the switch so we don't have to provide a pigtail to the to the switch terminal itself but here you see the ground wire from the two wire cable is attached to that back strap that's a metal strap inside a plastic box that is continuous out to the tab where the device screws would mount that receptacle and provide a ground for the for the frame with a switch through that grounding strap in there so now we'll change out that to a three-wire and show you how those connections should be made and how to comply with the new current code since 2011 so back in the camera out just a little bit this shows you the circuit in its entirety the power goes into that light box up here goes out of that light box to other parts of the circuit and then this two wire drop comes down to this switch now we're gonna switch that to wire from here to there out to a three wire and show you how the connections should be made now to comply with the code as of 2011 where it says you need to have a neutral in that box so I've changed out my two wires switch drop to a three wire so now we comply with the current code now keep in mind if something was wired to the code of the day you don't have to change it out I'm just showing you how it should be done now with the switch loop drop so I've changed out that to wire down to the switch to a three wire which is right here under the box you can see it so now here's the difference in splices we have our incoming neutral our cable that has a hot and a neutral in it incoming white get spliced to the outgoing white to the rest of the circuit as well as a pigtail now to our light fixture to our plastic chandelier so there's our pigtail there's our three other wires incoming outgoing and now outgoing as well a neutral down to the switch which we'll get to in a minute so grounds again all done properly around the ground terminal in the outlet box spliced together with the pigtail for a future light that's sitting here and we'll tuck all that back in neutrals all together including a pigtail to the light switch to the light fixture I should see power in power out and now power down to the switch on our black wire so we have all blacks together no more need to identify a white as a hot all three blacks are together and then they're returning read from that switch goes to our plastic chandelier or any other light fixture we'll go down to the switch and show you the changes that are made there so down at the switch box now a three wire cable instead of the two wire we've got a neutral that we can use for any kind of a control device motion sensor or dimmer switch any of the new electronic switching devices that might require neutral now it's here to be used we also have a hot wire that comes down out of the blacks place at the light box connected to our switch and then the outgoing red back up to the light fixture grounds of course tied the ground wire is looped around that terminal at the back of the box tighten down firmly and we'll leave this pigtail here for any other device that may also require a ground so there you have it we switched out a switch leg loop with only a two wire to a three wire cable and we now comply with the code as of 2011 remember you don't have to change anything that was wired to meet the code of the day they are grandfathered but it's always a good idea to have a neutral in that switch outlet box I can't tell you how many questions I've had on the website and on my comments in the YouTube channel saying can I add a receptacle to my switch and I only have a black and white wire so now you can understand why you can't add it with only two wires you could add it with three wires thanks again for tuning in don't forget to Like and subscribe to my channel here that way you'll know when I release new videos check out my website at electrical - online.com don't forget I have a new course on udemy at U de my.com that's learn the basics of household wiring and I have links below to that as well as that valuable resource the basics of household wiring DVD where you're gonna find all this and more information to make you a competent electrical weekend wiring warrior so thanks again I'm teri Peterman the internet electrician

Channel: Terry Peterman

Views: 241,774

Rating: 4.729425 out of 5

Keywords: switch, single pole switch, light outlet, light fixture, light switch, switch leg drop, switch loop drop, drop loop switch, two-way switch

Id: pnlHCiRN_RU

Length: 8min 31sec (511 seconds)

Published: Mon Jun 04 2018