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Acoustics & Electrical
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Discussion Starter · #1 ·
In practice and in education I follow the more recent versions of NEC 404 to include a grounded (neutral) conductor at switch locations. This article from IAEI discusses the reason being for accommodating modern occupancy controls and preventing putting current on the EGC. Sadly, many new electronic lighting controls are being made with a bond between the grounded (neutral) and EGC. Also, this article is a nice summary of Code history for this rule and expanding exceptions.



https://iaeimagazine.org/magazine/2...ded-conductor-at-that-switch-location-or-not/


But the main reason I practice this is to prevent the white wire from being used as 120V hot or switched hot when a single 12/2 or 12/3 is pulled to a switch. We've all seen posts and helped in the field when diagnosing how white insulated switched conductors are used, and rarely are the conductors re-colored. Re-coloring the grounded conductor for use as a switched conductor is allowed per 200.7(C) but I only do this in existing installations when I have no choice but to use the current configuration.


If you need a refresher of 200.7(C)(1) it reads as follows:



200.7 Use of Insulation of a White or Gray Color or with Three Continuous White or Gray Stripes:
(C) Circuits of 50 Volts or More:

(1) If a part of a cable assembly that has the insulation permanently re-identified to indicate its use as an ungrounded conductor by marking tape, painting, or other effective means at its termination and at each location where the conductor is visible and accessible. Identification shall encircle the insulation and shall be a color other than white, gray, or green. If used for single-pole, 3-way or 4-way switch loops, the re-identified conductor with white or gray insulation or three continuous white or ray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.



What is this forum promoting, typically, for the handling of white insulated conductors in switched circuits? Are you pushing 200.7(C)? In the recent post about 3-way switching I didn't see recommendations to re-color any switched or hot white insulated wiring. I was waiting for a better photo and more info. Maybe it was premature given the lack of usable info, hence the question to the group.


Cheers.
 

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In practice and in education I follow the more recent versions of NEC 404 to include a grounded (neutral) conductor at switch locations. This article from IAEI discusses the reason being for accommodating modern occupancy controls and preventing putting current on the EGC. Sadly, many new electronic lighting controls are being made with a bond between the grounded (neutral) and EGC. Also, this article is a nice summary of Code history for this rule and expanding exceptions.



https://iaeimagazine.org/magazine/2...ded-conductor-at-that-switch-location-or-not/


But the main reason I practice this is to prevent the white wire from being used as 120V hot or switched hot when a single 12/2 or 12/3 is pulled to a switch. We've all seen posts and helped in the field when diagnosing how white insulated switched conductors are used, and rarely are the conductors re-colored. Re-coloring the grounded conductor for use as a switched conductor is allowed per 200.7(C) but I only do this in existing installations when I have no choice but to use the current configuration.


If you need a refresher of 200.7(C)(1) it reads as follows:



200.7 Use of Insulation of a White or Gray Color or with Three Continuous White or Gray Stripes:
(C) Circuits of 50 Volts or More:

(1) If a part of a cable assembly that has the insulation permanently re-identified to indicate its use as an ungrounded conductor by marking tape, painting, or other effective means at its termination and at each location where the conductor is visible and accessible. Identification shall encircle the insulation and shall be a color other than white, gray, or green. If used for single-pole, 3-way or 4-way switch loops, the re-identified conductor with white or gray insulation or three continuous white or ray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.



What is this forum promoting, typically, for the handling of white insulated conductors in switched circuits? Are you pushing 200.7(C)? In the recent post about 3-way switching I didn't see recommendations to re-color any switched or hot white insulated wiring. I was waiting for a better photo and more info. Maybe it was premature given the lack of usable info, hence the question to the group.


Cheers.

Good topic. I have not pulled any cable in 3 years since I re-wired the home we are living in now. So I am not currently "up" on what residential cables are being made today, or the latest NEC codes.

Here is my interpretation of your post inquiry in my sketch below. We know the white in a "switch lop" has to be color changed to indicate, it is now a power carrying conductor or does it ?.

But I do not know how the present electricians are handling the required "neutral" conductor to be in the switch boxes of 3/4 way switch circuits, while using the standard 14-3 NM-WG or 12-3 NM-WG Romex cables as used in my sketch .

So has the residential cabling industry stepped up maybe, and are now manufacturing a Romex TYPE NM-WG that has 4 conductors in it ?

Or is the residential wireman supposed to just run an additional two wire cable along with the 3 wire cable between the 3 or 4 way switches to get the required neutral conductor ?

If they are, this would seem to me to be weird wiring practices just to meet the NEC code you mentioned above . Time for a 4 wire Type NM WG maybe ? ...

I dunnooo...
 

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Discussion Starter · #4 ·
Running power to the switch box 1st solves this problem, no? As opposed to the first stop being the light fixture. That's how I wired my house anyway.
Or are you only referring to retrofit applications?
You describe the best way to avoid this hassle altogether. Running power to the light fixture first was an old practice that I don't see done much anymore. It certainly makes for a very crowded box!

In a retrofit, you can only re-color the wires you encounter. Running new wiring to correct the existing condition is not usually feasible. I have encountered existing installations where I could revise wiring to bring the system into compliance, but it's not a common situation.
 

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Discussion Starter · #5 ·
Good topic. I have not pulled any cable in 3 years since I re-wired the home we are living in now. So I am not currently "up" on what residential cables are being made today, or the latest NEC codes.

Here is my interpretation of your post inquiry in my sketch below. We know the white in a "switch lop" has to be color changed to indicate, it is now a power carrying conductor or does it ?.

But I do not know how the present electricians are handling the required "neutral" conductor to be in the switch boxes of 3/4 way switch circuits, while using the standard 14-3 NM-WG or 12-3 NM-WG Romex cables as used in my sketch .

So has the residential cabling industry stepped up maybe, and are now manufacturing a Romex TYPE NM-WG that has 4 conductors in it ?

Or is the residential wireman supposed to just run an additional two wire cable along with the 3 wire cable between the 3 or 4 way switches to get the required neutral conductor ?

If they are, this would seem to me to be weird wiring practices just to meet the NEC code you mentioned above . Time for a 4 wire Type NM WG maybe ? ...

I dunnooo...
3- or 4- way switches create a bit of a challenge for compliance unless you wire intentionally and don't feed unswitched power to the light fixture first. If you bring 12/2 to the first 3-way you have a proper neutral. Then 12/3 as the traveler means you can keep the white wire as neutral (red/black are travelers). Continue as needed through 4-way switches to the last 3-way. Then 12/2 again between the last 3-way and the light. Simple and legal and no re-coloring of wiring necessary. This is how I wire switches.

No need for 12/4 if you avoid the old way of crowding the lighting box.

In modern commercial construction, we use digital lighting controls that just require a single CAT5E to a controller (when not using snap switches). So much is dimmed today that snap switches are less common. When used, the circuit is wired as I describe above (on my projects anyway).

The requirement to color-code wiring and re-color white or gray wiring when used for >50V does not have an exception (for our discussion topic) and should be done anytime it is encountered in the field. When I come across it, I take the time to investigate the entire circuit and re-color accordingly, adding labels or a description on the inside of the switchplate. Future me appreciates the notes, as would anyone else who encounters it later on. :)
 

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We all know that if a person is roughing in a new build, they can power the light FIRST and eleiminate the OP's point on not having a neutral conductor in the 3/4 way switching ciruit. ...

So there must be in the NEC an "exception" for the MILLIONS of homes in the USA that have the 3/4 way switches wired as in my sketch ??

Otherwise the OP here is a moot point to all the DIY'ers that come on here asking to wire up their Zwaves and such, on their 3 way /3 wire switch circuit in their existing, already wired homes.

The ones that have the power ran to the light first, on their 3/4 way switch circuits.

As there is no "neutral" between the 3/4 way switches that have the power going to the light first. in these old homes.

And because these homes that have the old "switch loop" wiring, they will not have a working neutral in the 3way/4 way switch boxes for a smart device or timer. So unless they rip out and do over their switch cabling, they cannot be compliant with the OP's NEC ruling.

So the OP is just to make people aware of the NEW wiring installs being done ?
 

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Discussion Starter · #7 ·
I'm the OP, and it's a two-fold post. First, to verify awareness and second to identify that yes, we should remind DIYers to re-color. That is how the NEC handles this - it says to provide the neutral for new installations and to re-color for existing installations.

I was prompted by another post, as noted, that let me to question how detailed this forum likes to get. I am impressed by the way this forum is managed and its contributors. Because of what I do, I have a desire to delve a bit deeper and make longer lists of corrections.
 

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Running power to the switch box 1st solves this problem, no? As opposed to the first stop being the light fixture. That's how I wired my house anyway.
Or are you only referring to retrofit applications?

Running power to the switch box first does allow for a neutral at
switch box, but, it doesn't supply a constant to any switch box
except the first one. Do any occupancy sensors etc work properly
with their power coming from the travellers?
 

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I'm the OP, and it's a two-fold post. First, to verify awareness and second to identify that yes, we should remind DIYers to re-color. That is how the NEC handles this - it says to provide the neutral for new installations and to re-color for existing installations.

I was prompted by another post, as noted, that let me to question how detailed this forum likes to get. I am impressed by the way this forum is managed and its contributors. Because of what I do, I have a desire to delve a bit deeper and make longer lists of corrections.
I am very aware that you KHA are the OP. And your OP here has sat idle for two days now from lack of interest. I think it is a bit rude of any forum to ignore an OP whether or not, their OP is a complex one ...or very simple one.

So I brought your OP to the top of the page this afternoon, when it THEN got some interest generated in it.

So very good. We are holding a class here based on a newer NEC rule.

I presented a sketch with a known issue which counters the NEC "neutral required in the switch box" rule. Immediately, the responses to my post are,

" Well. no one should take their power to the light on a 3 way switch circuit".

Well, yeah I agree, on new work of course not. But what should we out here today, do on our "old work" homes 3 way circuits that have no neutral in the boxes ?

What are people supposed to do that say, are re-wiring enough of their old home just "enough" to where it will require a permit and inspection. And their home has a few of the "switch loops" 3 ways circuits in their home, that are done like my drawing above..power to the light.

Should they rip all of their 3 way switch wiring out while busting open walls, to re-do the 3 way circuit wiring just to get the now "required neutral" in the switch boxes ?

When the inspector notes the old 3 way wiring and comments on the lack of neutral in them, what happens then ? Should the owner just tell their inspector their old 3 way "switch loop" wiring with no neutral in the switch boxes, should be "grandfathered" in and they will not be tearing out their old 3 way wiring ?
 

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Discussion Starter · #12 ·
What are people supposed to do that say, are re-wiring enough of their old home just "enough" to where it will require a permit and inspection. And their home has a few of the "switch loops" 3 ways circuits in their home, that are done like my drawing above..power to the light.

Should they rip all of their 3 way switch wiring out while busting open walls, to re-do the 3 way circuit wiring just to get the now "required neutral" in the switch boxes ?

When the inspector notes the old 3 way wiring and comments on the lack of neutral in them, what happens then ? Should the owner just tell their inspector their old 3 way "switch loop" wiring with no neutral in the switch boxes, should be "grandfathered" in and they will not be tearing out their old 3 way wiring ?
To the first part of your post: Understood and appreciated, genuinely. Thank you.

I think we can all agree that color coding is a necessary step for any installation, existing or new, and we can focus on the grounded conductor usage.

The neutral requirement is intended for occupancy sensors that require a grounded conductor to operate, and the desire by the NEC to prevent the EGC from being used in lieu of a grounded conductor. When the situation occurs where an existing project is in the situation you describe, the first question would be if a new device is being installed that requires a neutral. If the answer is no, then simply re-coloring the conductors could be reasonable given the existing wiring limitations. If the answer is yes, then wiring modifications to prevent using the EGC as a neutral would be prudent.

My preference in new installations or remodels where wiring is being re-done, is to comply and not use a white insulated wire as a traveler or switch leg. Stairwells are a hassle because that is an instance where 3-way switching is Code required and the old way of using 12/3 is the most cost effective approach.

I teach a class on home wiring at a local college, it is in evenings so adults can participate. We dedicate two days (4 hours) of hands-on wiring of lights/switches/receptacles and we encounter this conversation every time. I provide examples of wiring three devices that includes the light being the incoming unswitched 120V. I describe methods to achieve compliance with a variety of scenarios. I specifically address the questions you pose as it is highly likely they will all encounter it. I usually bring up a recent example where I've encountered this situation.

I apologize if it sounded like I was being dismissive of 90% of what people encounter as that wasn't my intent. I tried to acknowledge this by saying we should just encourage re-coloring.

As with any job, we first identify what you have to work with, what your options are, and what each solution has for pros/cons. When it comes to re-wiring switches, there are certainly several options. With wireless controls being more prevalent, we have another option that eliminates the need for re-pulling wire but may likely require an actual neutral and thus require changing how wires are assigned.

I don't expect an inspector to complain about the lack of a neutral when walls aren't re-built or exposed during a project. I think any new work should comply, but I personally would defend a homeowner who couldn't reasonably re-wire the entire lighting circuit just to add a neutral that wasn't used.
 

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Well, yeah I agree, on new work of course not. But what should we out here today, do on our "old work" homes 3 way circuits that have no neutral in the boxes ?

What are people supposed to do that say, are re-wiring enough of their old home just "enough" to where it will require a permit and inspection. And their home has a few of the "switch loops" 3 ways circuits in their home, that are done like my drawing above..power to the light.

Should they rip all of their 3 way switch wiring out while busting open walls, to re-do the 3 way circuit wiring just to get the now "required neutral" in the switch boxes ?

When the inspector notes the old 3 way wiring and comments on the lack of neutral in them, what happens then ? Should the owner just tell their inspector their old 3 way "switch loop" wiring with no neutral in the switch boxes, should be "grandfathered" in and they will not be tearing out their old 3 way wiring ?

-NEC code only applies to new construction, or when a substantial renovation occurs.


Example - a new addition onto the rear of a house will have to comply with having a neutral in the 3 way and 4 way switch locations. That doesn't mean inspector is going to meander into the front foyer - open the stairwell 3-way and demand rewiring because no neutral in the switch.


New codes apply to new work, except when concerning life safety.
 
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