# What is a switch loop?



## owl (Oct 31, 2012)

As the title would suggest, I knew to the trade. I heard this term at work, but I don't know what it is.


----------



## 360max (Jun 10, 2011)

owl said:


> As the title would suggest, I knew to the train. I heard this term at work, but I don't know what it is.


----------



## Meadow (Jan 14, 2011)

When power is first run to the light, a second cable/conduit is run to the switch to the light to control the light itself.


----------



## owl (Oct 31, 2012)

Is it more common to run power to the switch first? 

Thank you for the replies.


----------



## Dennis Alwon (May 9, 2009)

owl said:


> Is it more common to run power to the switch first?
> 
> Thank you for the replies.


It is more common in residential to feed the switch, but commercial jobs there is usually power in the dropped ceiling so you run a switch loop down


----------



## 220/221 (Sep 25, 2007)

Also, known in my area as a suicide switch (white wire hot) :thumbup:


----------



## owl (Oct 31, 2012)

Do people use switch loops in resi just because it is a more convenient route to wire? What is the reason for it?


----------



## 480sparky (Sep 20, 2007)

owl said:


> Do people use switch loops in resi just because it is a more convenient route to wire? What is the reason for it?



Most resi wiring is priced to be cheap and fast. If a switch loop can be done cheaper and faster, then it's done that way.


----------



## 480sparky (Sep 20, 2007)

220/221 said:


> Also, known in my area as a suicide switch (white wire hot) :thumbup:



Which was perfectly legal until the NFPA started to dummy down the NEC to help out those who aren't really 'qualified personnel'.


----------



## Meadow (Jan 14, 2011)

owl said:


> Do people use switch loops in resi just because it is a more convenient route to wire? What is the reason for it?


 

I often find it uses way less wire when running many ceiling lights each requiring switch control. By running a feed from box to box it is way cheaper than dropping a feed down to the switch, back up to the other switch plus a 3rd run up to the light box where another switch controlled light is only a few feet from it. So in such applications it cuts wire use literally in half or more.:thumbup:


----------



## owl (Oct 31, 2012)

Thanks, all. The diagrams really help. Much appreciated.


----------



## Reoknows (Dec 1, 2012)

So I ran a super switch loop the other day... constant power was in my switch box and I ran a 12/4 up to my box where I had an occ sensor. Line side power to the occ sensor, load side of occ sensor back down to the switch then load side of the switch to the lights. Couldn't think of a better way of doing it.


----------



## Vintage Sounds (Oct 23, 2009)

owl said:


> Do people use switch loops in resi just because it is a more convenient route to wire? What is the reason for it?


It's much more common in older homes from what I've seen. Mid 80s and earlier. One advantage is that it reduces the number of wires in the switch box at the expense of increasing the number of wires in the light box. If the splice fails then you have to take down the light to make a repair. Annoying when it's a regular light, *really* annoying when it's an expensive chandelier. Unless you use 3-wire cable for the loop, there won't be a neutral in the switch box which some devices like occupancy sensors, timers and some dimmers require. I think for these reasons it's no longer the standard for most homes(that I've encountered anyway). You might still see it for some things like a closet light, mechanical room or switched receptacle.


----------



## ElectricJoeNJ (Feb 24, 2011)

Reoknows said:


> So I ran a super switch loop the other day... constant power was in my switch box and I ran a 12/4 up to my box where I had an occ sensor. Line side power to the occ sensor, load side of occ sensor back down to the switch then load side of the switch to the lights. Couldn't think of a better way of doing it.


Why didn't you just switch the power going to the occ sensor. You coulda just ran a 12/2 unless you needed constant power in ceiling then you coulda ran a 12/3. You over complicated it.


----------



## Reoknows (Dec 1, 2012)

I did it like this because I have been told that switching the occ sensor is really bad for them. Not sure if there is any truth to that tbh but the guy running the job wanted it done that way. The switch is there so people can turn off the lights during the day or for a meeting or whatevers.


----------



## keepdry (Jul 24, 2012)

A lot of occ sensors have a start-up sequence they run through when power is applied. It is better to feed them hot.


----------



## Reoknows (Dec 1, 2012)

keepdry said:


> A lot of occ sensors have a start-up sequence they run through when power is applied. It is better to feed them hot.


Ahh thank you makes sense. Knew I was right lolz


----------



## danickstr (Mar 21, 2010)

with new NEC resi boxes need neutral so you can only run the switch loop with 14/3 or equivalent, to let a neutral dangle uselessly in the box.


----------



## Shockdoc (Mar 4, 2010)

AKA Dropback out here.


----------



## freeagnt54 (Aug 6, 2008)

danickstr said:


> with new NEC resi boxes need neutral so you can only run the switch loop with 14/3 or equivalent, to let a neutral dangle uselessly in the box.


Commercial boxes need them too, unless it's piped or the drywall is one-sided.


----------



## keepdry (Jul 24, 2012)

What code cycle started requiring that? Can anyone cite the number?


----------



## 480sparky (Sep 20, 2007)

keepdry said:


> what code cycle started requiring that? Can anyone cite the number?


2011. 4042.(c).


----------



## FastFokker (Sep 18, 2012)

We call it a "dead end switch" around here.


----------



## owl (Oct 31, 2012)

Reoknows said:


> So I ran a super switch loop the other day... constant power was in my switch box and I ran a 12/4 up to my box where I had an occ sensor. Line side power to the occ sensor, load side of occ sensor back down to the switch then load side of the switch to the lights. Couldn't think of a better way of doing it.


What is an occ sensor? I think I'll draw this one out to understand it better.


----------



## owl (Oct 31, 2012)

Also, how is the red in the three wire marked as neutral? White tape?


----------



## 220/221 (Sep 25, 2007)

owl said:


> Also, how is the red in the three wire marked as neutral? White tape?



The red shouldn't be used as a neutral because, if you need a neutral, there is a white available.  Right?


----------



## freeagnt54 (Aug 6, 2008)

owl said:


> What is an occ sensor? I think I'll draw this one out to understand it better.


Occupancy sensor (motion switch)


----------



## TGGT (Oct 28, 2012)

Reoknows said:


> I did it like this because I have been told that switching the occ sensor is really bad for them. Not sure if there is any truth to that tbh but the guy running the job wanted it done that way. The switch is there so people can turn off the lights during the day or for a meeting or whatevers.


Read the literature that comes with the device. The ones I've installed can come before, or after the switch. All it is, is another switch in the line, and I've used 12/2 with no problems.

Regardless when lights are powered by an OS, the manual toggle switch is just there as an override. People shouldn't be using it to control the lights on a regular basis.


----------



## Split Bolt (Aug 30, 2010)

FastFokker said:


> We call it a "dead end switch" around here.


Ditto in Northern Virginia!


----------



## Reoknows (Dec 1, 2012)

TGGT said:


> Read the literature that comes with the device. The ones I've installed can come before, or after the switch. All it is, is another switch in the line, and I've used 12/2 with no problems.
> 
> Regardless when lights are powered by an OS, the manual toggle switch is just there as an override. People shouldn't be using it to control the lights on a regular basis.


Yea that was the whole point of the switch (just an override). But it was a ceiling mounted occ sensor and its not good for the occ sensor to be turned on and off constantly. We all know its just there as an override but I guarantee you that they will constantly use the switch. Anyway if your power is in the switch box that is the only way to do it.


----------



## Reoknows (Dec 1, 2012)

owl said:


> Also, how is the red in the three wire marked as neutral? White tape?


You are over thinking stuff bro. It will all come together in time. Try to keep stuff as simple as possible.

But yea use the white as the neutral.


----------



## TGGT (Oct 28, 2012)

Reoknows said:


> Yea that was the whole point of the switch (just an override). But it was a ceiling mounted occ sensor and its not good for the occ sensor to be turned on and off constantly. We all know its just there as an override but I guarantee you that they will constantly use the switch. Anyway if your power is in the switch box that is the only way to do it.


Hook your line to your switch, send the load up to your Powerpack. 12/2, done.

What's the product number? I want to look up the literature on it. I just finished up wiring several rooms with overhead OS's and the powerpacks made it clear you could wire it before or after your override.

And what's the point of installing a OS if people are just going to regularly flip the switch anyway. The whole point is to conserve energy and for the convenience of not having to feel around for a switch in the dark.


----------



## Reoknows (Dec 1, 2012)

I mean I obv understand what you are saying and I would like to do it that way myself. I don't have the part number handy but I read it myself after this thread popped off a few months ago. I'll try to get it tomorrow and post it here.


----------



## Reoknows (Dec 1, 2012)

You have to have an override in a conf. rm/office no matter what. If they're doing some sort of a power point presentation or whatever they need to be able to turn off the lights.


----------

